Alt Reference: NOS/CDAS/REQ/0002
GB Operational Concept
Connected Driver Advisory System (C-DAS)
Electronic Version
CCMS No: 63931746
Issue status
Version
Status
Date
0.1
Draft document created
October 2012
0.4
Draft for internal review
December 2012
0.6
Draft published for external review
January 2013
0.7
Draft with corrected definitions
April 2013
0.8
Draft addressing review comments
May 2013
0.9
Draft addressing review comments
June 2013
0.10
Draft addressing review comments
June 2013
1.00
For approvals
July 2013
1.01
Typo correction in clause 1.2.3
September 2013
2.0 draft A
Update for Phase 2: HAZOP, Open Points resolution,
Assumptions Validation, Proof of Concept trials
October 2014
2.0 draft B
Update in line with peer review of v2.0 draft A
November 2014
2.0
For OSG
December 2014
2.1 draft A
Update in line with OSG comments and outcome of
Safety Analysis
April 2015
2.1 draft B
Draft addressing check comments. For FTG
May 2015
2.1
For signature
July 2015
Acknowledgements
The authors gratefully acknowledge help from many people across the industry in preparing this
document, and in particular the following:
•
Nick Thorley (Network Rail, Traffic Management project)
•
Mark Wardell (First Group)
•
Steve Price (ATOC)
•
Kevin Johnson & Andy Bundy (Freightliner)
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Date:
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Contents
Section
Description
1 1.2 1.3 1.4 1.5 1.6 Introduction
Background
Link to the 2012 Rail Technical Strategy
Purpose
Document Scope
References
4 4 5 6 7 8 2 2.1 2.2 Overview
High level requirements
Assumptions
9 9 9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 Operation of C-DAS
Operations Principles
System Design Principles
Energy Efficient Speed Profile Calculation
Information Displayed
Customising C-DAS
Driving With C-DAS
Train Preparation
Traffic Regulation with C-DAS
Driving Policy, Guidance and Training
RU Roles and Responsibilities
IM Responsibilities
System Maintenance
14 14 15 18 19 29 35 39 39 40 42 45 46 4 4.1 4.2 4.3 4.4 Open Points
Overview
Onboard DAS Operations
Train regulation with C-DAS
C-DAS System issues
47 47 47 49 49 5 Definitions
51 6 Appendix A Appendix B Abbreviations
System Concept Architecture
Open Point 2: C-DAS display in TSR and ESR areas
56 58 62 Network Rail
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1
Introduction
1.1
1.2
This document has been produced by Network Rail, acting on behalf of the Great
Britain (GB) rail industry, to specify the operational concept for a Connected Driver
Advisory System (C-DAS).
Background
1.2.1
1.2.2
The creation of an operational concept document is part of the GB rail industry’s
plan for the future implementation of a Driver Advisory System (DAS). With the
development of this document the operational concept for DAS now considers two
DAS variants, Standalone and Connected, although a third variant, Networked
DAS, will be included in the future:
a)
Standalone DAS (S-DAS) is a driver advisory system which has all
data downloaded to train at or prior to journey start.
b)
Networked DAS (N-DAS) is a driver advisory system that is capable
of communicating with one or more RU control centres, thus enabling
provision of data to the train, including updates for schedule or routing
information, though these are generally not in near real time.
c)
Connected DAS (C-DAS) is a driver advisory system with a
communications link to the IM control centre in each controlled area
in which the train operates. This enables the provision of schedule,
routing and speed restriction updates to trains in near real time, and
also receipt of information from trains to the IM control centre to
improve regulation decisions. In an uncontrolled area C-DAS will
operate with initial data (as per S-DAS), or with the most recent
updates received from an IM control centre or from RU-managed
system(s) (as per N-DAS).
The implementation of any DAS is intended to deliver benefits in the quality, cost
and efficiency of train operation. With S-DAS, the expected benefits are:
a)
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Improved Safety
i)
Train regulated to the working timetable - fewer restrictive
signals
ii)
Overall lower sectional running speeds
iii)
Advance warning of locations where speed restrictions change
iv)
Lower PSR / station approach speeds to PSRs / stations /
known conflict points with extended coasting
v)
Reminder of next station calling point, thus reducing missed
stations / overruns
b)
Improved fuel efficiency
c)
Reduced wear and tear due to reduced braking and lower running
speeds
d)
Improved capture of delay attribution data
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1.2.3
However, with S-DAS, benefits are not realised unless trains are on schedule (or
nearly so), i.e. typically ~75% of passenger journeys on major routes.
1.2.4
When DAS is operating in Connected mode (i.e. able to receive schedule updates
and to feedback train position to traffic regulation centres) the expected benefits
are all of those anticipated for S-DAS and in addition:
1.2.5
1.3
a)
Improved recovery from disruption
b)
Train regulation to revised schedule
c)
Support for regulation to optimise for network capacity or
performance (based on fewer delays due to red signals)
d)
Support for improved conflict resolution (based on trains’ predicted
running)
e)
Energy, carbon and wear and tear benefits are expected to be
achieved on upwards of 90% of journeys in comparison with 75%
(observed for inter-city passenger trains) of journeys with S-DAS, due
to schedule revisions being available near-realtime and thus usable
by C-DAS for late running trains.
f)
In addition, both DAS variants may support a future anticipated
capability to optimise energy consumption based on locally available
electrical power supply or power tariffs/budgets.
It is accepted that there are commercial issues associated with the implementation
of C-DAS related to the allocation of benefits between the different duty holders,
but these are considered to be out of scope of this document.
Link to the 2012 Rail Technical Strategy
1.3.1
The introduction of DAS has been identified in the 2012 Rail Technical Strategy as
one of the first steps towards realising the Control, Command and Communication
theme of the future railway vision. The strategy recognises the significant
contribution that DAS can make to railway operations by delivering the benefits
described in section 1.2 above, and is seen as a step on the path towards the
vision of an automated Railway controlled by an intelligent network management
system.
1.3.2
DAS implementation and operations may additionally support, or be supported by,
enabling activities described in the RTS as described in Table 1 below:
Network Rail
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Theme
Link with DAS
Energy
DAS supports the specification of development of energy efficient
railway assets through its capability to support energy
consumption reductions
DAS supports the optimisation of energy use through the
application of intelligent traffic management systems.
Information
DAS may be supported by the definition of common information
architectures and protocols, including activities associated with
improvements in information security resilience.
DAS may be supported by the use of COTS information
technologies
DAS may be supported by the activities associated with the
production of an optimized, cross-rail information flow model.
Customer
experience
DAS, and C-DAS in particular, may contribute to improving the
end to end journey experience
DAS, and C-DAS in particular, may support the accurate
provision of real-time customer information
Whole
System
Approach
DAS will be supported by the adoption of a whole system
approach to railway system management, planning, knowledge,
and business modeling.
Table 1 - Rail Technical Strategy Links
1.4
Purpose
1.4.1
The purpose of this document is to inform the development of technical
requirements and operational guidance for C-DAS implementation so as to
support consistency between different suppliers’ DAS products while allowing RUs
maximum flexibility in supporting their operational requirements.
1.4.2
The document supports the specification of the interface between Infrastructure
Manager and Railway Undertaking components of C-DAS which will be delivered
to the RSSB as a draft Railway Interface Standard in line with the rail industry
standards process.
1.4.3
The document will assist stakeholders in developing an understanding of how CDAS will affect them by:
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a)
Providing a common vision of C-DAS operation in GB for passenger
and freight operation.
b)
Providing a high level definition of the system boundary and
interfaces including system users and other affected roles and
systems.
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1.5
c)
Providing a broad, high level description of how the system will
operate in association with existing signalling infrastructure and
operational rules and processes on all types of routes, with their
different service patterns and types of traffic.
d)
Providing a description of the information required by drivers and IM
users of the system to deliver the required functionality.
e)
Providing a preliminary identification of the system data requirements
to support the display of the required C-DAS information to drivers.
f)
Providing information relevant to (but not limited to) the following:
i)
Infrastructure Manager (IM).
ii)
Railway Undertakings (RU), i.e. passenger train operating
companies (TOCs) and Freight Operating Companies (FOCs).
iii)
RSSB.
iv)
Association of Train Operating Companies (ATOC).
v)
Maintenance organisations for traction and rolling stock and
infrastructure.
vi)
System/equipment suppliers and integrators.
vii)
Department for Transport (DfT).
viii)
Office of Rail Regulation (ORR).
ix)
Rolling Stock leasing Companies (ROSCOs) and other vehicle
owners.
1.4.4
Although the content of the document is not itself mandatory, it can be used to
determine what could be mandatory in Railway Group Standards and other
specifications. The word ‘MUST’ indicates the potential for a future requirement.
1.4.5
Future work is planned:
a)
To ensure that this document is consistent with the concept of
operations for Traffic Management, ERTMS and ATO;
b)
To make provision for DAS operations and interfaces on ETCS-fitted
trains.
Document Scope
1.5.1
The scope of this document is the operation of C-DAS within the context of the GB
mainline railway. The document describes the key interfaces between train and
trackside as well as the operational guidance associated with its use.
1.5.2
The document works alongside the existing S-DAS document (whose structure it
shares), but aims eventually to supersede it. Its content has been informed by the
perceived need to provide an upgrade path to C-DAS from existing S-DAS
products which will be cost-effective both for RU customers and also for the DAS
product suppliers.
1.5.3
The following are excluded from the scope of this document:
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1.6
a)
The design of the working timetable.
b)
RT3973 restrictions and train-specific local instructions.
c)
The definition of the onboard algorithms for the determination of the
advisory information.
d)
The format of data and the means of exchange between involved
parties.
e)
Details of the communications carrier used to provide live info from
operational systems to DAS.
f)
The Driver Machine Interface (DMI) design.
g)
Commercial arrangements between dutyholders associated with the
implementation and operation of C-DAS.
1.5.4
The document has been informed by a Safety Analysis of the C-DAS system, see
[RD9].
1.5.5
This document reflects the outcome of trials undertaken to demonstrate the
feasibility of the concepts presented in this document.
1.5.6
A number of open points identified during the development of an earlier version of
this document have now been resolved and are reflected in the current document.
The open points and the working assumptions initially adopted for them are
documented in section 4. `
1.5.7
The analysis which delivered the resolution of Open Point 2: C-DAS display in
TSR and ESR areas is included as Appendix B.
References
[RD1]
GRIP Stage 1 Development Remit, Operational and Technical Requirements for
Driver Advisory System, Issue 1.1, 28 January 2011.
[RD2]
RSSB Research Project T724 Report (Stage 1 and 2), Driver Advisory Information
for Energy Management and Regulation, March and November 2009.
[RD3]
Railway Group Standard GO/RM/3056 Working Manual for Rail Staff, Freight Train
Operations, Issue 2, December 2003.
[RD4]
Rule Book GE/RT8000/TW1 Preparation and Movement of Trains – General,
Issue 8, October 2008.
[RD5]
S-DAS Operational Concept, Issue 1.0 (12th March 2012) Ref NS-FUTRO OC
(9001).
[RD6]
Network Rail Common Interface File: User Guidance Notes, Version 28.
[RD7]
Guide to the Train Driving Licences and Certificates Regulations 2010, Second
edition, published by the ORR, November 2012
[RD8]
National DAS Specification
CCMS:65266930 v1.0
[RD9]
National DAS Specification Project: C-DAS Safety Analysis, CCMS:65112234 v1.1
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Assumptions
Validation
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2
Overview
2.1
High level requirements
2.1.1
C-DAS must have the capability to provide driver advisory information in both
controlled and uncontrolled areas that, if followed, will enable the driver of a CDAS fitted train to manage train speed so as to minimise deviations from the
current schedule and, where possible, reduce energy consumption.
GN1
The need to provide driver advisory information in uncontrolled areas imposes
requirements for the onboard C-DAS subsystem to have access to the
application data for the journey being undertaken at or before journey start.
GN2
It is also the basis of the design decision that advisory information
calculations are performed in the onboard C-DAS subsystem, as this allows
C-DAS to operate autonomously in uncontrolled areas, i.e. when out of
contact with the trackside.
GN3
Note that even in a controlled area trains cannot be assumed to be in
communications contact with the off-train C-DAS subsystem at all times (see
Assumption 2.2.3.7).
2.1.2
C-DAS fitted trains operating in a controlled area must be capable of receiving
updated application data at any time using agreed, pre-defined, communication
protocol rules and formats. The updates may include revised arrival, passing and
departure times at timing points and/or rerouting onto a different line or to a
different destination, and any new or changed temporary or emergency speed
restrictions.
GN4
The need to support trains in a controlled area imposes requirements for the
onboard C-DAS subsystem to have access to the planned schedule and any
schedule updates which may affect it.
GN5
The need to support re-routed trains in a controlled area imposes additional
requirements for:
2.1.3
Assumptions
2.2.1
General
Network Rail
A means to identify to the onboard C-DAS subsystem the line
the train is running on.
b)
The onboard C-DAS subsystem to have access to the
appropriate application data for each line on which the train
operates.
In a controlled area, the C-DAS system must be capable of providing train
movement information to the Traffic Management System that will facilitate
accurate prediction of future movements of C-DAS fitted trains.
2.2
2.2.1.1
a)
The purpose of the assumptions listed below is to document the context in
which the C-DAS system operates and in certain cases identify requirements
on systems that interact with C-DAS. Where possible, the project or
organisation responsible for validating the assumption has been included –
see the text in square brackets included at the end of the assumption.
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2.2.1.2
2.2.2
Other than those tagged as DAS System Specification (which are in effect
high level design decisions) these assumptions have been validated in line
with [RD8].
System Boundary
2.2.2.1
The C-DAS comprises on-train and off-train subsystems, and includes an offtrain subsystem which provides an interface with the IM’s Traffic Management
system.
[DAS System specification]
2.2.2.2
Responsibility for the following lies outside the scope of C-DAS:
[Traffic Management project]
a)
Calculating revised train schedules
b)
Monitoring train location (other than self-monitoring by the onboard CDAS subsystem)
c)
Route setting
d)
Monitoring signalling states.
2.2.2.3
C-DAS will generally operate in the context of a Traffic Management system
which has the capability to revise the schedules and/or routing of trains in the
area it controls. However it will also be capable of operating whenever it has
access to application data that is consistent with current operations.
[DAS System specification]
2.2.2.4
Schedule updates and/or routing updates, as and when available, are made
accessible to C-DAS by external systems.
[Traffic Management project]
2.2.2.5
All planning data and infrastructure geography data (track geography,
network models and track features), permissible speeds and speed
restrictions other than RT3973 restrictions, and train consist data, will be
made available by infrastructure-based systems external to C-DAS at an
appropriate level of accuracy and quality.
[Traffic Management project, ITPS, Asset Information]
2.2.2.6
Current train performance characteristics will be available to the onboard CDAS subsystem without the involvement of Traffic Management.
[DAS System specification]
2.2.2.7
Current train performance characteristics, if available to Traffic Management,
have the potential to support regulation decisions.
[Traffic Management project]
2.2.2.8
Train movement data and predictions (position, speed, time etc.), if available
to Traffic Management, have the potential to support regulatory decisions.
[Traffic Management project]
2.2.2.9
The movement of ‘grey’ trains has no impact on C-DAS but is considered by
Traffic Management in the determination of schedule updates based on
assumed train performance characteristics, and train movement data based
on train detection inputs, or from other data sources that provide train location
data, for example ERTMS position reports or other onboard systems
equipped with GNSS.
[Traffic Management project]
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2.2.2.10
2.2.3
Traffic Management has the potential to benefit from C-DAS fitted trains
acknowledging receipt of any schedule updates.
[Traffic Management project]
System Operation
2.2.3.1
Calculation of advisory information is based on current schedule,
infrastructure geography, permissible speeds qualified by applicable speed
restrictions, and train performance characteristics.
[DAS System specification]
2.2.3.2
The Applicable Timetable forms the default schedule data unless further
schedule updates (VSTP) are provided.
[DAS System specification]
2.2.3.3
A schedule for a C-DAS fitted train is accessible at the time of C-DAS setup
on the train.
[Traffic Management project]
2.2.3.4
Schedule data is available to the C-DAS system at the level of granularity
required for correct operation on the route.
[Traffic Management project, ITPS]
2.2.3.5
In a controlled area, updates to schedule, routing or speed restrictions will be
provided by Traffic Management sufficiently in advance to allow C-DAS to
support effective regulation.
[Traffic Management project]
2.2.3.6
In a controlled area communications between C-DAS onboard and off-train
subsystems will, in principle, be continuously available and of adequate
capacity to support effective traffic regulation, although in practice there may
be breaks in connectivity.
[DAS Communications specification]
GN6
In a controlled area, schedule, routing or speed restriction updates may be
provided by the traffic management system at any time. However 100%
availability of communications between train and trackside can never be
guaranteed and it cannot therefore be assumed that the train has access to
all updates generated at the trackside
2.2.3.7
C-DAS will use multiple communications service providers and negotiate
communications improvement at Route level. Requirements for coverage
should be conveyed into NRT’s Business Plan for CP5 (see Open Point 11).
[DAS Communications specification]
2.2.3.8
The primary input to C-DAS is the current schedule and C-DAS needs no
visibility of, for example, the optimisation criteria used by Traffic Management
in setting the schedule.
[Traffic Management project]
2.2.3.9
The introduction of Traffic Management Systems will not be accompanied by
any significant changes to operational rules and practices in respect of
informing drivers of changes to speed restrictions or stopping patterns. For
this reason changes to speed restrictions or stopping pattern may be
introduced into C-DAS via Traffic Management or otherwise without any preconditions. That is, drivers will continue to receive ESR notifications, Special
Stop orders, Not-to-Stop orders etc. in the manner appropriate to the method
of signalling.
[Operational analysis, HF analysis, Traffic Management project]
GN7
Examples of particular relevance to this document include the following,
which are applicable for all situations where speed restrictions are displayed
on lineside signage:
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2.2.4
a)
The lineside signage will be in place before the corresponding
data is available to the Traffic Management system; similarly any
updates to a TSR will be shown on the signage first. Hence CDAS will not receive TSRs, TSR updates or ESRs before they
are ‘boarded’.
b)
Traffic Management will not specify a TSR speed lower than the
published value; the TSR will be replaced by an ESR if a lower
speed than the published value is needed. Hence any TSR
speed received by C-DAS will be no lower than the published
value, and any lower speed will be managed as an ESR.
GN8
Ongoing deployment of C-DAS, and any future enhancements to it may be
associated with changes to operating practices.
2.2.3.10
Assumption superseded by resolution of Open Point 1.
[DAS System Specification, HF analysis]
2.2.3.11
Operators and systems in the ROC will have a need to distinguish between
the following for each train in the control area (see Open Point 7):
[Operational analysis, Traffic Management project]
a)
C-DAS fitted and working.
b)
C-DAS fitted but not working (i.e. disabled).
c)
S-DAS fitted.
d)
No DAS fitted.
2.2.3.12
The Infrastructure Geography data and permissible speed data (including
PSRs) for the scheduled route and any likely alternative re-routing on which
C-DAS is required to operate will be downloaded to the onboard C-DAS
system at or before journey start and stored persistently (see Open Point 8).
[DAS System specification, Asset Information, Traffic Management
project, Communications specification]
2.2.3.13
Infrastructure Geography, Permissible Speed, TSR, ESR and planned and
current schedule datasets will include a means based on track link identifiers
which the onboard C-DAS subsystem can use to match the operating line,
schedule and geographical limits of permissible speeds and speed
restrictions to each other at the level of the individual track (see Open Point
8).
[DAS System specification, Asset Information, Traffic Management
project, Communications specification]
Driver Operation
2.2.4.1
Driver training for C-DAS (as for S-DAS) will mandate that drivers will never
prioritise DAS speed advice over safety or professional judgment.
[Safety analysis, Operational Analysis]
GN9
This assumption provides a rationale for allowing C-DAS to give advisory
information that may be incorrect, rather than withholding advisory information
unless its correctness can be guaranteed. Examples where this would be
relevant would generally be limited to situations where the on-train C-DAS
system had not received updates to application data generated by Traffic
Management or other off-train systems:
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a)
advice speed that exceeds an ESR, or does not take account of
a changed stopping pattern
b)
advice speed that does not take account of train rerouting
c)
advice speed that is inconsistent with a restrictive aspect (yellow
or double yellow).
It might also occur where application data available to the C-DAS is incorrect,
e.g.
d)
2.2.5
TSR start and end locations disagreeing with lineside signage.
2.2.4.2
Assumption superseded by updated 2.2.3.9.
[HF Analysis, Operational analysis, Traffic Management project]
2.2.4.3
Drivers will be trained to recognise and ignore an advice speed if it exceeds
the speed value associated with a TSR or ESR (see Open Point 2 and
Appendix B).
[HF analysis, Operational Analysis, Safety analysis]
GN10
The driver may be helped to achieve this by C-DAS display of selected
Customisation data, especially route look-ahead (see clause 3.4.3.4 and
associated GNs)
2.2.4.4
Changes in advisory information will not be accompanied by audible tones.
[HF Analysis]
Operational context
2.2.5.1
Traffic Management systems are expected to be deployed piecemeal across
the GB network, and will not initially be available in all areas where trains with
C-DAS capability will operate. [Traffic Management implementation plan]
GN11
This has a significant impact on C-DAS operations, because it places a
requirement for smooth transitions for trains which pass between controlled
areas (where updated control information will generally be made available to
the C-DAS system) and uncontrolled areas (where updates can not be
expected).
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3
Operation of C-DAS
3.1
Operations Principles
3.1.1
GN12
3.1.2
GN13
3.1.3
GN14
3.1.4
GN15
3.1.5
GN16
Information provided to drivers by C-DAS is wholly advisory. The advisory nature
of the information displayed by the C-DAS onboard subsystem must be clearly
defined and communicated to drivers.
The hierarchy that drivers are expected to apply in following messages and
information they are presented with is as follows:
a)
Safety related information (out of scope of C-DAS).
b)
Optimising performance, and
c)
Optimising environmental savings.
The advisory information displayed by the C-DAS must not lead to unacceptable
workload demands on drivers or cause unacceptable distraction from other driving
activities. The C-DAS must not impact negatively on safety.
C-DAS should only display information that is useful to the driver and has the
potential to enhance his/her driving technique..
C-DAS must not advise drivers on when to brake.
Information provided by the C-DAS system is advisory only – the driver
remains responsible for identifying situations where braking is required,
assessing braking conditions, and applying the level of braking appropriate to
the situation.
Speed information must be displayed by the C-DAS in the same units employed
by the in-cab speed display.
Trains which are not ETCS-fitted display speeds in mph. In addition it is
possible for ETCS-fitted trains in the UK to be capable of displaying speeds in
mph regardless of ETCS Level in accordance with the ‘Specific Case’ in the
CCS TSI (see GE/RT8402: ERTMS/ETCS DMI National Requirements). It is
therefore possible that speeds on ETCS fitted trains could be displayed in
mph regardless of ETCS operating level, or in mph when not operating under
ETCS supervision (Level NTC and Level 0) and in km/h when operating
under ETCS supervision (Levels 1, 2 and 3).
Distance information must be displayed by the C-DAS in the same units employed
by other in-cab distance information (for example that provided by ETCS), or
trackside distance information where in-cab information is not provided/available.
On ETCS fitted trains, distance information is displayed in metric units
(kilometres and metres) - there is currently no ‘Specific Case’ in respect of
distance units. Distances displayed by C-DAS would similarly be required to
be in metres or kilometres.
3.1.6
Switching between speed and distance units must be performed automatically.
3.1.7
The C-DAS driver interface must not duplicate display information which is already
provided to the driver where there is the potential for confusion or distraction, for
example, current train speed.
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GN17
3.1.8
GN18
3.1.9
GN19
Situations in which the C-DAS should not display duplicate information
include any of the following:
a)
Where the information is already displayed by an equipment of
higher integrity.
b)
Where the information displayed by the other equipment is
derived from a different source.
The C-DAS system should for preference not require a driver to re-enter any data
that has already been input to another on-train system.
Dual entry unnecessarily extends setup time, increases the opportunity for
error and is moreover perceived by drivers to be user-unfriendly. However the
RU should consider whether the cost of obtaining data from another system
can be justified.
Driver operation with DAS should as far as possible be the same in controlled and
uncontrolled areas.
If behaviour were to be different the driver’s workload would be complicated
by the need to be aware whether the train is in a controlled area or
uncontrolled area and to change operational behaviour accordingly. This
would be further complicated by the probable additional need to recognise
and adapt to degraded communications in a controlled area.
3.1.10 Drivers must not be required to acknowledge receipt of data updates or changes
to advisory information.
3.1.11 Absence of a working or fully functioning C-DAS must not be taken as a reason to
take a train out of service, or to delay it whilst repairs are carried out. Trains may
enter service from a depot without a working or fully functioning C-DAS.
3.2
System Design Principles
3.2.1
The C-DAS onboard subsystem must keep conflicts between advisory information
and safety critical information to a minimum by suppressing the display of advisory
information in circumstances where the potential for such conflicts is high.
3.2.2
The C-DAS onboard subsystem must calculate and display information to the
driver in sufficient time for the driver to react safely and efficiently to changes.
3.2.3
The algorithms employed by the C-DAS system must assume a train dependent
braking profile will be applied on the approach to scheduled stopping points and
when braking to a lower target speed.
GN20
The assumed train dependent braking profile may be that imposed by an
onboard automatic train protection system (e.g. GW-ATP, TVM430, ETCS)
and may include allowances for RU driving policies.
3.2.4
The information displayed by the C-DAS onboard subsystem must be designed so
that it is readable and intuitive, and must support the driving task while keeping
driver distraction to a minimum.
3.2.5
The RU must develop the design, and the in-cab location, of the C-DAS display in
consultation with ROSCOs, vehicle manufacturers and drivers, and in accordance
with human factors good practice.
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GN21
Means should be considered to ease the consultation process; these might
include a driver interface designed to be easily reconfigurable.
3.2.6
Any data preparation processes generating data for C-DAS operation must employ
a level of checking appropriate to the accuracy and correctness of the data
required to support safe and efficient C-DAS operations.
3.2.7
The C-DAS user interface for data entry must be designed to reduce the likelihood
of input errors.
GN22
3.2.8
GN23
3.2.9
Techniques for achieving this include:
a)
Minimising manual data entry
b)
Obtaining ‘common’ data automatically from other onboard
systems (e.g. C-DAS setup data and selected train specific data
items from ETCS).
Where the manual input of data is required, the process for manual entry must be
such that the risk of incorrect data being utilised by the system is minimised to an
acceptable level.
There are a number of strategies that could be employed to reduce the risk of
incorrectly entering data, including:
a)
Presenting data items for selection from a predefined list rather
than requiring data to be manually typed in.
b)
Range and value checking on entered data.
c)
Once data has been entered requiring the user to check and
confirm that the entered data is correct.
The RU, in consultation with ROSCOs and vehicle owners, should consider the
level of potential integration between the C-DAS onboard subsystem and other
onboard systems.
GN24
The level of potential integration between C-DAS and other onboard systems
may vary according to whether the C-DAS equipment is to be retrofitted to
existing stock or fitted to new stock. There may be trade-offs required
between the lower costs of an entirely independent application, and benefits
resulting from sharing services, data or equipment with other existing or future
applications: e.g. positioning equipment, GNSS or communications antennas,
time source, TMS etc. RUs should also consider consolidating information
and/or displays to minimise the number of DMIs and the possibility of
conflicting information being shown. Higher levels of integration should be
sought, especially for new design rolling stock.
GN25
Requirements and guidance for onboard integration between C-DAS and
ETCS on ETCS-fitted trains will be addressed in a future version of this
document (see clause 1.4.5).
3.2.10 The RU, in consultation with ROSCOs and vehicle owners, should consider
whether to provide an interface between the C-DAS and the existing onboard data
recording equipment for the purpose of recording C-DAS related operational data
(see section 3.5.4 of this document). If an interface is not implemented, a means
must be provided for data recorded on separate systems to be synchronised.
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3.2.11 The C-DAS system must be capable of sending and receiving data updates to and
from traffic management at any time whilst operating in a controlled area.
GN26
This aims to promote a system design in which data updates are received as
soon as they become available from the Traffic Management System and are
delivered promptly to the target trains, in order to maximise the effectiveness
of C-DAS. It precludes a design that would allow C-DAS to receive or forward
data updates only at specific locations and / or times.
3.2.12 C-DAS must support the secure, remote installation of upgrades to the onboard CDAS software.
3.2.13 C-DAS must support the secure, remote update of data that is held onboard, for
example, infrastructure geography data, train specific data, and user data.
3.2.14 The IM should consider the provision of a facility for the secure, remote installation
of upgrades to the off-train C-DAS software and/or updates of off-train user data.
3.2.15 There must be no control interface between C-DAS and the onboard braking and
traction systems.
3.2.16 The C-DAS time source must provide time information within the tolerances
required to meet the current schedule.
3.2.17 All information displayed to the driver must be in English.
3.2.18 The way in which application data is provided to the C-DAS onboard subsystem
must:
a)
Allow the train to operate as S-DAS or N-DAS (i.e. using only preinstalled data, and for N-DAS any updates received, and for only as
long as the train operation is compatible with that data).
b)
Enable the C-DAS to provide driver advisory information whenever
the train operation is consistent with the most recent data it has
received.
GN27
This reflects the expectation that during the period while Traffic Management
systems are being rolled out, TOCs / FOC’s will apply C-DAS products on
fleets that operate on routes where the trackside can support C-DAS (i.e.
have the capability to provide updates to trains) only on some parts of the
route if at all. It is important during this period to enable TOCs / FOC’s to use
their systems to achieve performance benefits and energy savings even
where supporting IM systems are not available. This requires C-DAS to be
able to operate in ‘autonomous’ mode, using either pre-loaded or revised
data.
GN28
This has implications for the way in which Infrastructure Geography and
Permissible speed data are made available to the onboard DAS subsystem
(Assumption 2.2.3.12 refers).
3.2.19 A means must be provided to notify the C-DAS when the current running line is not
the line to which its advisory information applies, for example as the result of a
schedule update (containing a change of route or running line) which has not been
received in advance by the C-DAS (Open Point 1 refers).
GN29
Network Rail
Options for achieving this include detecting a change of route by some
technical means, and/or using a driver control.
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GN30
This facility would be useful where there are diversionary routes or lines,
including from fast to slow line (or vice versa) or bi-directional running, when
the C-DAS has not received advance notification of a routing change. It is
anticipated that such notifications would generally be available in controlled
areas, but not in uncontrolled areas.
3.2.20 The overall impact of activities associated with C-DAS onboard subsystem start up
and setup on railway timing and driver workload must be minimised.
3.2.21 In a controlled area, the C-DAS onboard subsystem must be capable of advising
the traffic management system if a fault or failure is detected that affects C-DAS
functionality, if it is possible to do so.
3.2.22 Where required by the RU, the C-DAS onboard subsystem must support the
manual initiation of a subsystem functionality test and the on-demand
communication of functionality test results.
GN31
Manual initiation of a functionality test might support the driver in determining
if the system is operating correctly in situations where driver confidence in the
information being presented is questioned.
3.2.23 The C-DAS system must be developed in accordance with industry good practice
with regard to any hardware or software development, test and release processes,
so that the delivered system is suitably robust and reliable.
3.2.24 The C-DAS system must be developed to at least SIL-1 standards.
GN32
The rationale to support this is documented in [RD9].
3.2.25 The system design must consider measures identified in [RD9] to improve hazard
mitigation, to include:
a)
A reliability requirement for any technical facility (if there is one) used
by C-DAS to detect the current running line
b)
A reliability requirement aimed at preventing frozen C-DAS displays
c)
A means to ensure that data is routed to and received by the correct
train.
3.2.26 The system design must consider measures to ensure that correct and current
versions of customisation datasets are shared between C-DAS on-train and offtrain subsystems.
GN33
3.3
Such measures would typically include versioning schema and checking
protocols.
Energy Efficient Speed Profile Calculation
3.3.1
GN34
The C-DAS onboard subsystem must calculate and provide accurate advisory
information that supports the driver in meeting the current schedule in an energy
efficient manner.
Research project T724 [RD2] states that to provide optimum energy efficiency
the advisory information presented to the driver should be calculated so that it:
a)
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Limits the maximum speed.
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GN35
b)
Minimises braking.
c)
Uses the traction system (including regenerative braking) in its
most efficient power setting.
For rolling stock with regenerative braking an appropriate energy efficient
strategy may be to limit the maximum speed but allow for an increased rate of
deceleration (according to the capability of the regenerative brake).
Achieving optimum energy efficiency may potentially be qualified by other
research including any Energy Efficient Driving Technique (EEDT) research
undertaken by the RU.
3.3.2
Calculation of an energy efficient speed profile must take account of the
application and setup data defined in section 3.5.1.
3.3.3
When configuring the C-DAS processing algorithms, account must be taken of the
particular type of route, service pattern, traffic type (passenger, freight etc.) and
driving policy (see also clause 3.9.1).
3.3.4
The C-DAS processing algorithms must be capable of being configured to meet
changing operational requirements.
3.4
Information Displayed
3.4.1
Classes of information
3.4.1.1
GN36
Network Rail
The C-DAS must be capable of displaying two classes of information:
a)
Advisory information, whose purpose is to provide recommendations
to the driver;
b)
Selected Customisation data, whose purpose is to indicate to the
driver the data which the C-DAS is currently using as the basis of its
calculations. Customisation data displayed for this purpose includes
journey segment and route look-ahead information (section 3.4.3),
train consist information (section 3.4.4) and system information
(section 3.4.5).
Displaying Customisation data may mitigate risk by enabling the driver to
compare his/her knowledge with the data being used by the C-DAS, and thus
to evaluate the C-DAS advice. Specifically, it enables the driver to distinguish
the following three situations and to react accordingly to the C-DAS advisory
information:
a)
Customisation data display coincides with what the driver already
knows; in this case the display serves to reinforce that knowledge.
b)
Customisation Data display shows information that is not yet known
to the driver; in this case the display prepares the driver for
upcoming changes. (Examples might include: a schedule update,
or an ESR which has already been boarded..
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c)
Customisation data display does not reflect driver knowledge; in this
case the display serves to notify the driver that the C-DAS data is
not fully up to date, with the result that s/he knows to discount CDAS advisory information in favour of driver knowledge. (Examples
might include: train rerouted from fast to slow line or vice versa, a
change to stopping pattern, a TSR where the lineside signage
differs from published details, or a new ESR whose data has not yet
been made available to the C-DAS.)
GN37
Displaying Customisation data may also mitigate risk by highlighting
anomalies (e.g. driver data entry errors, or the line for which the advisory
information is applicable differing from the train’s current location) thus in
effect prompting the driver to take appropriate action.
GN38
The C-DAS should make a clear visual distinction between the C-DAS
advisory information and the C-DAS customisation data.
3.4.1.2
The amount of information displayed must be consistent with the size and
positioning of the display screen and in line with human factors best practice.
GN39
Table 2 below shows minimum and recommended display configuration
options for the information described in the following sub-sections.
Information type
Status
Notes
Advisory Information
Current advice
Mandatory
Approach advice
Mandatory
Approach countdown
Recommended
Customisation data - Journey segment / Route look-ahead
Next station stop
Recommended
Next Timing Point
Useful
Scheduled arrival
Useful
Estimated arrival
Useful
Current Running Line and
direction of travel
Strongly recommended
Less important on single line
Current location
Recommended
Useful if the driver has to contact the signaller
Timing points
Permissible speeds
TSR locations & speeds
Gives reference scale
Recommended if space
permits – mitigates for
missing incorrect TSR /
ESR data
ESR locations
Confirms driver knowledge
Helps driver evaluate advice
Helps driver evaluate advice
Customisation data - Train consist
Formation (passenger)
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Recommended
Useful reminder
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Orientation (passenger)
Useful
Mass, length (freight)
Strongly recommended
Mitigation against incorrect data entry
Strongly recommended
(freight);
Mitigation against incorrect data entry (freight)
Current maximum speed
Reduced performance
Recommended
(passenger)
Useful reminder
Strongly recommended
Useful reminder
Customisation data - System info
Connectivity indicator
Mandatory
Screen frozen indicator
Mandatory
Current time
Strongly recommended
Unless already displayed by another on-train system
Table 2 – Display options
3.4.2
Advisory Information
3.4.2.1
The C-DAS user interface must be capable of displaying the following types
of advisory information to the driver at the same time:
a)
Current.
b)
Approaching.
GN40
The purpose of providing current advisory information is so that the driver has
the benefit of knowing what the C-DAS is proposing at the current location of
the train.
GN41
The purpose of providing approaching advisory information is so that the
driver has the benefit of preparing for any future change in advisory
information.
3.4.2.2
The current advisory information displayed to the driver must be at most one
of the following:
3.4.2.3
GN42
Network Rail
a)
The currently advised speed value.
b)
Other advisory information relevant to the operational situation as
determined by the RU.
The approaching advisory information displayed to the driver must be at most
one of the following (see clause 3.4.2.6):
a)
A new advised speed value that is approaching.
b)
Other approaching advisory information relevant to the operational
situation as determined by the RU.
Various advisory information display options have been trialled by various
operators to determine the driver preferences. The options trialled were:
a)
A time based display of early or late running.
b)
A graphical representation of the recommended speed profile.
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c)
Text based advice of the speed to drive at, or to coast.
GN43
One of the results of the trial (which was on non-ETCS fitted trains) indicated
that a text based speed value option (option c above) was overwhelmingly the
preferred option. (This result is supported by the review of existing systems
reported in [RD2] Appendix 1.) The other two options were found to be
difficult to interpret, distracting, and increased driver workload.
GN44
Other advisory, or approaching advisory, information might include, for
example:
a)
Notification that the train is within a Coasting area or instruction to
Coast. Coasting may be advised, for example, on the approach to a
lower advice speed value or to a station stop. The RU may determine
it appropriate for the driver to be informed why coasting is being
advised.
d)
No specific advice offered, which might include details of why no
specific advice is offered. Situations where no specific advice may be
available might include, for example:
i)
The calculated advice speed value is greater than or equal to
the lowest of the linespeed profile (permissible speeds modified
by any relevant TSRs, ESRs) or train specific speeds and the
maximum train speed.
ii)
Application data is not available for the journey segment.
3.4.2.4
The C-DAS must only display advisory speed values (current or approaching)
that have been calculated as no higher than the lowest of the linespeed
profile (permissible speeds modified by any relevant TSRs, ESRs) or train
specific speeds and the maximum train speed. The RU may additionally
consider the definition of a minimum advised speed value.
GN45
This prevents the display of mandatory speed information to the driver by an
advisory system which could present a safety risk if the information is
incorrect. A minimum advice speed may prevent drivers trying to drive at
speeds that are so low that controlling the train becomes difficult.
GN46
The RU should consider whether the C-DAS may display an advisory speed
value which is less than or equal to the lesser of the linespeed and the
maximum train speed, or only a speed which is strictly less than this value.
GN47
An advisory speed may be displayed except where an ESR is known to be in
force, thus including areas with or without a TSR. However when deciding
policy for displaying TSR speeds the RU should take into account the risk of
drivers placing undue reliance on the C-DAS display in preference to
following lineside signage, particularly when lighting conditions are poor.
GN48
Until ESR data becomes dependably available to the DAS, it is recommended
that the C-DAS should not display an advisory speed value for an ESR area,
but should indicate the reason why no advice speed is offered, e.g. by
displaying “ESR” (see also Appendix B). A similar recommendation applies to
areas affected by a blanket speed restriction.
3.4.2.5
The conditions under which displayed advisory information is refreshed must
be controlled, and configurable.
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GN49
3.4.3
Properly controlling the refresh conditions will reduce driver distraction as the
presented information will not be changing too frequently. Possible means of
achieving this control might include:
a)
Incremental limits to be imposed for the display of advisory
speed e.g. the speed is displayed in 5 mph or 5 km/h increments
only (8mph/ km/h hysteresis).
b)
Time limits to be imposed between changes of advisory
information.
3.4.2.6
The C-DAS must only display approaching information if a change in advisory
information occurs within a distance or time defined by a configurable ‘lookahead’ parameter.
GN50
The ‘look-ahead’ parameter determines how far ahead, in distance or time
from the current train position, the C-DAS is permitted to display approaching
advisory information.
GN51
It is important to set the ‘look ahead’ parameters so that approaching advisory
information is only displayed to the driver when it is useful to do so. For
example, it may not be desirable to provide information to the driver of a
change in speed which occurs ten miles ahead. The ‘look ahead’ parameter
may be route or location specific.
3.4.2.7
A countdown display (or similar functionality) to a change in advisory
information may be provided so that the driver can determine when or where
the actual change in advice starts.
GN52
The countdown display may indicate a time or distance until the change in
advisory information, or a simple progress bar, the value or length of which
steadily decreases at discrete intervals as the train approaches the change
location. For example the countdown display could show a time to a change
location starting with 1 minute (‘look ahead’ parameter) decreasing to 30s
then 20s, 10s down to 1s. The form of the countdown display should be
assessed in consultation with drivers and in accordance with human factors
good practice.
3.4.2.8
The C-DAS must provide a means to indicate to the driver when the receipt of
new data results in a change to advisory information (current and / or
approach advice) is to take effect within less than a pre-defined look-ahead.
GN53
This aims to bring the driver’s attention to an imminent change in advisory
information, typically arising from an operational incident, without requiring
him/her to monitor the C-DAS display constantly. The facility should be
designed so as not to distract the driver beyond what is necessary to bring
the unexpected change to his/her attention. Options might include display of a
different colour or on a different colour background, or a display which flashes
for a fixed length of time.)
GN54
The look-ahead may be defined in terms or distance or time.
Journey Segment and Route Look-ahead Information
3.4.3.1
C-DAS must support the display of journey segment information.
3.4.3.2
The provision, format and content of the journey segment information display
must be configurable by the RU and may include, for example:
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3.4.4
a)
The name of the next station stop or timing point.
b)
The scheduled arrival time at the next station stop or timing point.
c)
The estimated time of arrival at the next station stop or timing point.
d)
The scheduled departure time, and a countdown indication to the
scheduled departure time when a train is at a stand in a departure
station.
e)
The current estimated train location.
f)
The line to which the current advisory information is applicable where
this is important for speed control.
GN55
Displaying the line to which current advisory information is applicable might
support the driver in determining if the advisory information is appropriate to
the line the train is actually operating on.
3.4.3.3
C-DAS must support the display of route look-ahead information.
3.4.3.4
The provision, format and content of the route look-ahead information display
must be configurable by the RU and may include, for example:
a)
A distance scale.
b)
Stations and / or other timing points.
c)
Speed limits and start and end locations for Permissible Speed and
TSR data being used by the C-DAS.
d)
Start and end locations for ESR data being used by the C-DAS.
GN56
The route look-ahead display might for example show the maximum permitted
linespeed in a similar manner to the planning area on the ETCS DMI. The
driver would then be able to spot easily any discrepancy between the absent
or incorrect TSR or ESR that s/he was expecting (from WONs, signaller
notification or lineside signage) and would be less likely to follow the incorrect
advice.
GN57
The RU should determine how C-DAS should visually distinguish ESR areas
on the display of route look-ahead information. The RU should consider
whether C-DAS should distinguish areas affected by a blanket speed
restriction in a similar manner.
Train Consist Information
3.4.4.1
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C-DAS must support the display of train consist information that is considered
useful to the driver. The provision, format and content of the train consist
display must be configurable by the RU and may include, for example:
a)
On passenger trains, C-DAS could display the current train formation,
e.g. 4 cars or 12 cars, to assist the driver in identifying a platform stop
location.
b)
On freight trains, C-DAS could display train length and train mass.
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c)
GN58
3.4.5
3.4.6
On all trains, C-DAS could display maximum train speed, or details of
defective equipment affecting train operations entered by the driver
during setup (See section 3.5.2 of this document).
Train consist information forms part of the C-DAS setup information described
in section 3.5.2 of this document.
System Information
3.4.5.1
The driver must be provided with an indication to show when the C-DAS
onboard subsystem is in communications contact with a Traffic Management
system.
GN59
This is aimed at maintaining drivers’ confidence in the system, by making
them aware when regulating or routing updates can and cannot potentially be
received.
3.4.5.2
A means must be provided to allow the driver to determine whether the user
interface display has ‘frozen’.
GN60
This must be noticeable, but the design should consider the potential for
driver distraction. Solutions may include, for example, a current time display
with a 1 second refresh rate.
3.4.5.3
The C-DAS must be capable of displaying the current local clock time. The
provision and format of current time display must be configurable by the RU.
GN61
Local clock time will be based on UTC. The use of a 24-hour clock format is
recommended.
Information Display Conditions
3.4.6.1
Advisory and journey segment / route look-ahead information (if configured)
must only be displayed if the customisation data for a journey segment is
available to the C-DAS onboard subsystem.
GN62
Depending on where in the journey segment the train is when the application
data element is received, it may include only the subset of the application
data applicable to the remainder of the journey segment and/or journey. The
onboard subsystem will require train performance data and user data to be
available, and for setup to be completed before advisory, and other
information can be displayed.
3.4.6.2
The display of advisory and journey segment / route look-ahead information
(if configured) must be automatically suppressed when C-DAS detects that
the train’s actual position is not consistent with the specified journey.
GN63
This (see also 3.2.19) ensures that the driver will not be presented with
advisory or journey segment / route look-ahead information for an incorrect
route which could lead to trains being advised to drive slower than required to
meet the timetable, or being advised to drive at a speed higher than the line
can support. It also prevents advisory information being presented if the
train’s position cannot be determined. Journey data (see section 3.5.4 of this
document) may continue to be recorded while the information display is
automatically suppressed so as to allow the RU to assess the impact of the
suppression.
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3.4.6.3
Any known positional uncertainty inherent in the means C-DAS uses to
determine train position must not lead to the incorrect automatic suppression
of the C-DAS display.
GN64
The means that C-DAS uses to determine train position may have inherent
positional uncertainty. The design of the automatic suppression algorithm
should consider these uncertainties but not apply them too restrictively and
assume that the train is off route when this cannot dependably be determined.
3.4.6.4
The display of advisory information must be automatically suppressed if the
system detects that the driving is not consistent with the current advisory
profile. The condition used to detect this situation must be configurable, and
will likely be dependent on some combination of time, distance, speed and
heading.
GN65
The driving may not be consistent with the current advisory profile if the driver
was responding to restrictive signal aspects that the C-DAS system will not be
aware of (See assumption2.2.2.2d)) or braking on the approach to an ESR
which has not been conveyed to the on-train C-DAS system. When
configuring the detection of such situations, consideration should be given to
the risk of driver distraction if the display flips between suppressed and
unsuppressed states too frequently.
GN66
Signal aspect information will not form part of the information provided by
traffic management. RUs may consider it appropriate to trigger the automatic
suppression of C-DAS by means of other onboard systems ‘detecting’ that the
train is running on restrictive signals, for example the receipt of an AWS
warning. The RU should consider the benefit of using this means to avoid
distracting the driver when restrictive aspects are applied, against the
consequence that the effectiveness of C-DAS will be curtailed where PSRs
and TSRs are applied.
GN67
RUs may also consider requiring drivers to manually suppress C-DAS in
situations where the advisory profile cannot be followed (see 3.6.2.2 for
manual suppress and unsuppress).
3.4.6.5
The display of advisory, journey segment / route look-ahead and train consist
information (if configured), must be automatically suppressed when C-DAS
detects that ATO has been engaged.
GN68
The automatic suppression may be as a result of engaging ATO manually.
3.4.6.6
The display of advisory information must be automatically unsuppressed if,
following automatic suppression, and in the absence of any other suppression
condition, the system detects:
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a)
That the train’s actual position is consistent with the specified journey
(see clause 3.4.6.2) – possibly as a result of being routed back to a
route for which application data is available.
b)
That the driving is within a predefined tolerance of the current
advisory profile (see clause 3.4.6.4). This could, for example, be due
to the train speed changing such that it falls within the specified
tolerance of the current advisory profile, or the C-DAS onboard
subsystem recalculating advisory information following receipt of a
schedule update.
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c)
That ATO is disengaged.
GN69
When configuring the detection of these situations, consideration should be
given to the risk of driver distraction if the display flips between suppressed
and unsuppressed states too frequently.
3.4.6.7
The C-DAS must have the capability to include pre-defined suppression areas
in order to avoid advisory information distracting the driver in complex areas
where there is likely to be high workload, or where for other reasons there is
little benefit in providing advisory information.
GN70
Suppression areas could include the approach to, within, and departing from
stations or other complex areas. The RU should determine areas where
advisory information should be suppressed using a suitable risk based
approach.
3.4.6.8
The display of current advisory information must be automatically suppressed
while the train is within a pre-defined suppression area.
GN71
Approaching advisory information may be retained so that the driver is aware
of what the advisory information will be when the train leaves the suppression
area.
3.4.6.9
On leaving a pre-defined suppression area, C-DAS must automatically
unsuppress the display of advisory information.
3.4.6.10
The C-DAS driver interface must not display advisory information if C-DAS
has been manually suppressed.
GN72
The RU should consider whether or not to display journey segment / route
look-ahead information (where configured) when C-DAS has been manually
suppressed.
3.4.6.11
The C-DAS driver interface must not display advisory information, journey
segment / route look-ahead or train consist information (where configured), if
C-DAS has been disabled.
3.4.6.12
Table 3 below summarises the information to be displayed in the various
system states. A tick indicates that the information type can be displayed
subject to other conditions being met.
Display Information Type
System Status
Current
Advisory
Information
Approaching
Advisory
Information
Journey
Segment /
Route lookahead
Information
Train
Consist
Information
Journey
data
recording
Display not suppressed, system
not disabled


 [1]
 [1]

 [1]

Automatic Suppression (Off
Route, see clause 3.4.6.2 of this
document)
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Automatic Suppression
(Inconsistent Driving, see clause
3.4.6.4 of this document)
 [1]
 [1]

Automatic Suppression (ATO
Engaged, see clause 3.4.6.5 of
this document)
 [1]
Automatic Suppression
(Suppression Area, see clause
3.4.6.7 of this document)

Manual Suppression (see
section 3.6.4 of this document)
 [1]
 [1]

 [1] [2]
 [1]

Disable (see section 3.6.4of this
document)
Table 3 - Information displayed vs. system states
[1]
Display of this information is retained in the corresponding ‘System Status’,
but only if the RU has opted to display it in the unsuppressed case
[2]
Subject to the reason for manual suppression (see section 3.6.4 of this
document)
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3.5
Customising C-DAS
3.5.1
Overview
3.5.1.1
The C-DAS onboard subsystem must be customised with the data necessary
to allow the information described in section 3.4 of this document to be
calculated for a particular journey segment and displayed to the driver.
GN73
The necessary customisation data may not necessarily all be available prior
to or at journey start; it may become available during the journey after which
the C-DAS on board subsystem may provide advisory and other information.
GN74
The on-train DAS must not be permitted to operate on any route for which
current data is not available.
3.5.1.2
The data required to customise the C-DAS onboard subsystem can be
divided into four components:
a)
b)
c)
Network Rail
Application data, which includes:
i)
Infrastructure geography data – track geography (centre line,
curvature, altitude), track features (station / junction locations,
etc.), timing point locations, and network models.
ii)
Planned schedule (routing, departure and arrival times at
station stops and timing points).
iii)
Schedule updates i.e. changes to the planned schedule.
iv)
Routing updates.
v)
Permissible speeds including PSRs.
vi)
Temporary speed restrictions (TSRs).
vii)
Emergency speed restrictions (ESRs).
Train specific data, which includes:
i)
Current train acceleration and braking characteristics (taking
into account any reduced performance capabilities, for example
due to train defects).
ii)
Power consumption characteristics (e.g. traction and hotel
power consumption, efficiency etc.).
iii)
Current maximum train speed (taking into account any
limitations due to, for example, train defects).
iv)
Train weight profile.
v)
Train length.
vi)
Current power mode (applicable only to a train that is capable
of operating in different power modes: electric / diesel traction
or electric overhead/ third rail).
Setup Information (See section 3.5.2 of this document).
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d)
3.5.2
User data, which specifies those user definable characteristics of a
particular C-DAS onboard subsystem, for example:
i)
Which information is displayed and when, for example journey
segment / route look-ahead information, departure countdown
timers etc. (see section 3.4.6 of this document).
ii)
Specific display formats (colour, font, on-screen location etc.)
for the various information types displayed.
iii)
The content, format and display conditions for the non-advisory
information (see sections 3.4.3, 3.4.4 and 3.4.5 of this
document).
iv)
Information related to the definition of suppression areas (see
section 3.4.6 of this document).
v)
Approaching advisory information look-ahead parameters (see
section 3.4.2 of this document)
GN75
There is an aspiration that the application data will, in future, include electrical
energy consumption limitations due to physical supply limitations or energy
tariffs (by time of day, geographic location etc.).
GN76
If information to support it is available, the train weight profile data may
include a measure of passenger loading.
C-DAS Setup
3.5.2.1
Before the start of a particular journey, the C-DAS onboard subsystem must
be primed with setup information relevant to the train and the journey being
undertaken.
GN77
The setup process consists of inputting the following setup information into
the C-DAS onboard subsystem:
a)
Driver ID,
b)
Train Running Number (TRN),
c)
Train consist information,
d)
Train specific data corresponding to existing train faults or
failures.
GN78
Setup information could be entered or selected by the driver, or obtained
automatically from other onboard or off-train systems; for example, freight
train consist could be obtained from TOPS.
3.5.2.2
Manual entry or selection of C-DAS setup data must only be performed when
the train is at a stand.
3.5.2.3
Where required by the RU, C-DAS must support the identification of the driver
using a unique Driver ID.
GN79
To support the collection of accurate driver usage information where required
by the RU.
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GN80
The Driver ID may consist of an all numeric, alpha, or alphanumeric value.
This flexibility enables RUs to use an existing number already used to identify
train driving personnel within their organisation, for example, the Train driver
licence number as per [RD7].
GN81
On the ETCS DMI, the Driver ID data entry field consists of two lines. Each
line is capable of displaying up to a maximum of eight characters. Therefore
it may be advisable for RUs to limit the length of the Driver ID to a maximum
of eight characters to facilitate consistency with any future ETCS
implementation.
GN82
Consideration should be given to whether C-DAS should be interfaced to any
existing means provided in the driving cab for the entry of Driver ID (for
example: an electronic tag or swipe card reader).
3.5.2.4
The C-DAS must have the means to identify the journey using a TRN.
GN83
TRNs are used to differentiate between train services, giving each train its
own identity, which can be used for train planning, regulation or
communication purpose. However, on the GB mainline railway, the same
TRN can exist for many different services on the same and different parts of
the network.
GN84
For C-DAS, the TRN allows for the determination of the relevant application
data (route geography, schedule etc.) to be utilised by C-DAS for a particular
journey. Consideration should be given to providing a means for the TRN to
be obtained from another onboard system.
GN85
In GB a TRN currently consists of a 4-character alphanumeric headcode (for
example, 1L26), which contains three items of information:
a)
Class of train.
b)
Destination, stopping pattern or other form of service
differentiation.
c)
Train/route number.
3.5.2.5
C-DAS must initially support GB alphanumeric TRNs (‘headcodes’).
3.5.2.6
C-DAS must support a migration to eight digit TRNs, or any other future
format.
3.5.2.7
C-DAS must provide the means for driver to enter the TRN by either:
a)
Selecting or confirming a TRN from a chronological list which
corresponds with the known train location and time.
b)
Manually typing the TRN.
GN86
Selecting the TRN from a list reduces the opportunity for error that would be
incurred if the TRN were to be entered manually and allows for discrimination
between duplicate TRNs.
3.5.2.8
The C-DAS must provide the means for the driver to confirm that the system
has identified the correct journey from the TRN provided.
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GN87
This could be achieved by displaying the journey start and end points, and
any relevant “via” points in between, and departure time information
determined from the entered TRN and requiring that the driver confirm it is
correct.
3.5.2.9
Where the system has identified the incorrect journey, the driver must be
provided with the means to correct the error.
GN88
This error may have arisen due to:
a)
The system identifying the journey for an incorrectly entered or
selected TRN
b)
The system identifying the incorrect journey for a correctly
entered TRN.
3.5.2.10
A means must be provided for C-DAS to determine the actual train consist.
GN89
This information could be entered or selected manually by the driver, or
provided by other onboard or off-train systems.
GN90
Train consist information includes acceleration capability, train length, weight
and maximum speed. For passenger trains it could also include the
identification of isolated or unavailable traction motors because this impacts
on train acceleration capability. Additionally, train faults that lower the
maximum speed of a train, for example broken windows or raised emergency
bypass switches, might also be defined and input into the system, either
manually by the driver, or detected automatically from other systems, to
ensure that advisory information does not exceed the maximum speed of the
train.
GN91
For freight trains, train consist information, identified by a TRN, is available
via TOPS and is presented to the driver in the form of a train consist sheet
[RD3]. Train consist information could therefore (preferably) be acquired by
the C-DAS off-train subsystem from TOPS and downloaded to the C-DAS
onboard subsystem. Alternatively the driver could enter the relevant
information from the train consist sheet manually.
GN92
To reduce the risk of incorrect train consist information being entered
manually, drivers should where possible be presented with predefined lists
from which the relevant train consist information is selected; for example,
drivers of fixed formation passenger trains could be provided with various
formation options for selection. Manual entry of train consist information
should be avoided where possible, but where it is necessary appropriate
means should be employed to reduce the risk of error as described in section
3.2 of this document.
GN93
Consideration may also be given to allowing for the driver entry or selection of
information related to changes in passenger train orientation i.e. changes to
the normal location of specific coaches, for example buffet cars or first class
sections, within a passenger train formation. This information could be used
to minimise the occurrence of extended station stopping times through the
early advice of changes to passengers via passenger information systems, or
for catering services to adjust the locations for loading of buffet car stock.
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3.5.2.11
For trains that may be ‘Bi-mode’ powered, a means must be provided to
identify to the C-DAS onboard subsystem the power mode in which the train
is currently operating.
3.5.2.12
The C-DAS onboard subsystem must have the ability for the driver to enter
the power mode manually.
3.5.2.13
The C-DAS onboard subsystem must provide the means for the driver to
enter reduced maximum speed or changes to other performance parameters
associated with train defects.
GN94
Performance parameters might include, for example, reduced traction or
braking capability.
3.5.2.14
The C-DAS onboard subsystem must provide the means for the driver to
check and confirm that the current train consist information has been entered
/ selected or downloaded correctly.
GN95
If the train consist data does not accurately represent the train to be operated,
the advisory information provided to the driver may not be optimised which
may have a negative impact on train regulation and performance.
3.5.2.15
Where train consist information is downloaded from an external system, the
driver must notify the source of that information of any errors and request a
correction.
GN96
The corrected data should preferably be downloaded to the train in the same
way as the original faulty data. However manual correction of downloaded
train consist information may be supported, possibly subject to the necessary
corrections being verbally agreed with the source system operator.
3.5.2.16
C-DAS operation must be enabled only if the following conditions are all met:
a)
The driver has entered and/or confirmed setup information (see
3.5.2.1 and GN77)
b)
The driver has selected and/or confirmed train schedule (see 3.5.3.2
to 3.5.3.3)
c)
Current and correct train specific data is available (3.5.2.10 through
3.5.2.15)
d)
All the data required to be available to the on-train C-DAS at or prior
to journey start has been transferred and confirmed current (see
3.5.3.4).
3.5.2.17
Other than train consist, setup information from a completed journey must not
be retained by the C-DAS onboard subsystem.
GN97
It is generally preferred that train consist data should also be re-entered at the
start of a journey in order to reduce the likelihood of C-DAS using incorrect
data if the formation has changed.
GN98
The RU should take into consideration the following when deciding whether
the driver should be required to enter train consist / formation at the start of
each journey, or whether this data may be retained by the C-DAS system
from the previous journey and presented to the driver for confirmation:
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3.5.3
a)
The feasibility of making the retained data available to the driver
correctly and reliably
b)
The benefit of reduced setup time against the risk of C-DAS
using wrong data
c)
The possibility that the train consist / formation may have
changed
d)
Consistency of driver actions at start of journey in relation to
other on-train systems and to C-DAS fitted on other classes of
train driven by the same drivers.
Customisation Data Flow
3.5.3.1
Setup information and associated train specific data must be transferred from
the onboard C-DAS subsystem to Traffic Management.
GN99
This includes when setup is completed at the start of a journey and following
any subsequent changes during the journey, e.g. Driver ID and or TRN.
Changes to train specific data could be as a result of changes in train consist
data, or change of power mode, or as a result of driver checks identifying
errors in entered, selected or downloaded data.
GN100
Other means of conveying changes to train specific data to Traffic
Management may be utilised, subject to the condition that it can be ensured
that a common view of the train performance is shared between Traffic
Management and C-DAS.
GN101
This exchange of data should occur where possible; i.e. it is not necessarily
expected that a train would have to transfer data to traffic management when
setup is completed in an unconnected area, but it is recognised that for
effective regulation the traffic management system should have knowledge of
the train characteristics before the train starts operating within the controlled
area.
3.5.3.2
The schedule for the train must be transferred to the onboard C-DAS at each
change of the Train Running Number as part of C-DAS setup.
GN102
The C-DAS onboard subsystem will generally obtain the schedule from the CDAS off-train subsystem.
3.5.3.3
If the C-DAS onboard subsystem cannot obtain the schedule from the C-DAS
off-train subsystem, then it must obtain it from another source at or prior to
journey start.
3.5.3.4
Infrastructure Geography data together with permissible speeds for the
scheduled route and any possible diversions must be transferred to the CDAS onboard subsystem at or prior to journey start (see Assumption
2.2.3.12).
3.5.3.5
A means must be provided to enable C-DAS to confirm at or prior to setup
that infrastructure geography and permissible speeds for the relevant routes
and train types are available and current.
3.5.3.6
Any updates to the planned schedule or to speed restrictions relevant to the
journey (e.g. ESRs) must be transferred to the C-DAS onboard subsystem
when it is possible to do so.
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3.5.4
GN103
It may be possible to transfer this information to the train at or prior to journey
start if starting inside a controlled area, or during the journey when the train is
in a controlled area.
3.5.3.7
User data must be available to the C-DAS onboard subsystem at or prior to
journey start.
GN104
User data forms part of the C-DAS onboard subsystem configuration and is
necessary to support setup. User data may be updated as part of a system
upgrade, rather than as part of an application data transmission.
Journey Records
3.5.4.1
The C-DAS must record the details of each C-DAS journey so that the impact
of DAS on network performance can be evaluated.
GN105
The recorded details should include: actual and advisory speed profiles, setup
information (see section 3.5.2 of this document), and any Driver input. It may
also include other available information that will support off-line comparison of
energy usage, adherence to current schedule etc. over a period of time.
3.5.4.2
The C-DAS must continue to record journey data when the information
display is suppressed.
GN106
This allows the effect of the suppression to be assessed.
3.5.4.3
A means must be provided for journey records to be downloaded or
transferred from the train by the RU.
GN107
This may be via manual access to recording equipment on the train, or via
remote access at:
a)
Fixed locations during or at the end of a journey, or
b)
Fixed times, or
c)
At any time or location before, after or during a journey.
3.5.4.4
The RU may consider the provision of a means for the C-DAS onboard
subsystem to provide feedback to drivers on their ‘driving efficiency’
immediately after a journey.
GN108
This information could be provided, for example, as an indication of
adherence to current schedule during the journey and/or as energy usage for
the journey in the appropriate units (kilowatts per hour, litres per mile etc.).
The RU should determine how best to provide this information (it should be
useful and easily understandable) while considering the potential impact on
train interface requirements.
3.6
Driving With C-DAS
3.6.1
Overview
3.6.1.1
The driver must treat the information provided by the C-DAS as advisory only
and continue to drive in accordance with current rules, route knowledge and
operational notices .
3.6.1.2
C-DAS must provide advisory information that supports drivers in meeting the
following driving goals identified by Research Project T724 [RD2]:
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3.6.1.3
3.6.2
a)
Maintain the schedule of the service (“as far possible, [ensure that]
the trains runs to time and any avoidable delay is prevented”; p.9,
[RD4]).
b)
Apply additional driving guidance in best practice (such as
professional driving) and RU specific initiatives (section 5.3.1 of [RD2]
“Eco-driving”: Improving energy efficiency of service delivery).
The driver’s ability to achieve the (highest priority) goal of maintaining safety
(identified by Research Project T724 [RD2], “safety duties take priority over all
other duties”; p.9, [RD4]), must not be diminished by the implementation of CDAS.
C-DAS Driver Controls and Indications
3.6.2.1
The driver must only operate/interact with C-DAS when it is safe to do so,
such that it does not detract from their normal operating duties.
GN109
In order to avoid driver distraction, the C-DAS onboard subsystem could be
configured to make sure that certain functions are available for use only when
the train is at a stand. This could be effected either by C-DAS equipment
configuration or by the development of operator procedures.
3.6.2.2
The driver must be provided with a control to manually suppress the display
of DAS information.
GN110
Situations that require the display of C-DAS information to be automatically
suppressed are described in section 3.4.6. Manual suppression gives drivers
the ability to suppress the display in situations which do not trigger automatic
suppression, in preference to risking being distracted by inappropriate or
incorrect advice. Display information that is suppressed is defined in 3.4.6
Table 2.
3.6.2.3
The driver must be able to determine via the user interface that the display of
DAS information is being suppressed (following manual or automatic
suppression, see section 3.4.6 of this document).
GN111
Consideration should be given to indicating whether the suppression is
automatic or manual.
3.6.2.4
The driver must be provided with a control to unsuppress the display of DAS
information.
3.6.2.5
The manual unsuppress control must only function if the display of advisory
information has been manually suppressed and no automatic suppression
conditions apply.
3.6.2.6
The driver must be provided with the means to manually disable the C-DAS
onboard subsystem.
GN112
Situations that require C-DAS to be manually disabled are described in
section 3.6.4.
3.6.2.7
The driver must be provided with a means to identify that the C-DAS onboard
subsystem has been manually disabled.
3.6.2.8
The driver must be provided with the means to manually re-enable C-DAS.
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3.6.2.9
Once the C-DAS subsystem has been disabled all setup information must be
reset and will need to be re-entered after the C-DAS onboard subsystem is
re-enabled.
GN113
If the C-DAS is disabled journey records will not be produced.
3.6.2.10
The driver must be provided with an indication if the setup process is
unsuccessful (see also 3.5.2.16).
3.6.2.11
The C-DAS user interface must be capable of switching between predefined
night and day default brightness settings.
GN114
This switching could be provided automatically or by manual intervention from
the driver.
3.6.2.12
The driver must be provided with a control to manually adjust the brightness
of the C-DAS display from the night/day default settings within a predefined
minimum and maximum brightness range.
3.6.2.13
It must not be possible for the driver to reduce the brightness such that
displayed information is not visible.
3.6.2.14
Automatic switching, if provided, must not reduce the brightness such that
displayed information is not visible.
3.6.2.15
Automatic switching, if provided, due to detected low ambient light conditions
must occur quickly enough that drivers are not distracted by an over-bright
display, for example when entering a tunnel.
3.6.2.16
Automatic switching, if provided, must be controlled so that it is not triggered
unnecessarily by short duration events, for example the train is passing under
a bridge.
3.6.2.17
C-DAS must provide a holdover capability to allow driver change without
requiring full setup.
GN115
If the removal of the master key results in a loss of power to the C-DAS
onboard subsystem, setup information may need to be re-entered or
confirmed when the onboard subsystem is re-powered. A holdover capability
would allow the C-DAS onboard subsystem to remain operative for a period
after the cab is shut down to enable a driver to leave the cab or for driver
change to take place mid-journey.
3.6.2.18
Where the identification of the driver using a unique Driver ID is required,
drivers must be provided with the means to enter a new Driver ID at driver
changeover, without having to re-enter all other setup information.
3.6.2.19
The driver must be provided with the means to amend train consist
information without having to re-enter all the setup information.
GN116
The facility to amend train consist data during a journey is essential in order
to facilitate train operation at locations where changes are planned or
anticipated. Changes to train consist may result from coupling or uncoupling
or freight trains loading or unloading during a journey.
GN117
In the event that the train consist has changed during the driver changeover,
or the driver handover is taking place at the start of a new journey with a new
TRN, the relevant setup information will need to be amended.
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3.6.3
3.6.2.20
The driver must be provided with the means to amend TRN data without
having to re-enter all other setup information.
3.6.2.21
If the RU intends to utilise C-DAS journey records as part of network
performance monitoring processes, then:
a)
The driver must be provided with the means to manually select or
input explanatory information that describes why the C-DAS advisory
information was not followed during a journey.
b)
The driver must be provided with the means to manually select delay
attribution codes in the event that the service is delayed.
c)
The explanatory information and delay attribution code must be
recorded in the journey records and be available to the IM.
GN118
The user interface should provide a predefined list of explanatory information
and delay attribution codes from which the driver can select. The RU should
determine the requirements for the explanatory information that drivers can
access, but as a minimum it must be self-explanatory and easy to
discriminate.
GN119
Examples of explanatory information include:
a)
Infrastructure faults.
d)
Low adhesion.
e)
Poor weather.
f)
Train fault.
g)
Request stops.
3.6.2.22
Where C-DAS is required to provide advisory information for the train’s
current route, but is displaying advisory information for a different route, a
means must be provided for the driver to manually select the current route.
GN120
This control would typically be used to trigger a change to advisory
information when there is a change of route or running line that has not been
notified to the C-DAS in advance.
GN121
The user interface should reduce distraction risk, e.g. by providing the driver
with a simple predefined list of line ids from which to select.
GN122
The driver should be permitted to operate this control while the train is in
motion, provided that s/he considers it safe to do so.
Onboard Safety Systems
3.6.3.1
C-DAS must not affect the driver’s use of, existing onboard safety systems
(DRA, DSD, DVD, AWS, ERTMS etc.) in accordance with existing rules and
procedures.
3.6.3.2
Failure of the C-DAS system must not compromise the operation of safety
critical systems
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3.6.4
3.7
Abnormal Operations
3.6.4.1
The driver must be able to manually suppress the display of advisory and
journey information if the train has been re-routed and the C-DAS onboard
subsystem continues to display advisory or journey information associated
with the original route (see section 3.4.6 of this document).
GN123
Manual suppression of out-of-context information when the train has been
rerouted ensures that the driver will not be presented with advisory
information for the incorrect route which could lead to trains being advised to
drive slower than required to meet the timetable, or being advised to drive at
a speed higher than the line can support.
3.6.4.2
The driver must be able to manually disable the C-DAS onboard subsystem
for moves into, within and out of possessions and worksites.
3.6.4.3
The driver must be able to manually disable the C-DAS onboard subsystem in
the event that its operation becomes degraded.
GN124
This may include any planned outages to amend or upgrade C-DAS
equipment where this will result in a reduction of service during the
changeover, or the driver becoming aware of a C-DAS onboard subsystem
failure, for example ‘screen freeze’.
3.6.4.4
The C-DAS onboard subsystem should either be manually disabled or the
display suppressed if the driver is informed of the need to operate over
degraded infrastructure. This includes examination of the line, temporary
block working, single line working, and wrong direction movements. The RU
must consider which of the two options is preferable, i.e. disabling C-DAS or
suppressing the display.
3.6.4.5
The C-DAS onboard subsystem should either be manually disabled or the
display suppressed in the event of operational incidents. Examples would
include moving the train following a train failure, or the reduction of
infrastructure availability due to a bridge strike or broken rail. The RU must
consider which of the two options is preferable, i.e. disabling the C-DAS
onboard subsystem or suppressing the display.
Train Preparation
3.7.1
GN125
3.8
It must be possible to incorporate any additional train preparation tasks associated
with the C-DAS onboard equipment; whilst limiting the overall impact on workload
and timings through the efficient sequencing of train preparation activities.
The introduction of C-DAS will increase the amount of onboard equipment.
This equipment may require additional activities to be undertaken during train
preparation. Examples of additional train preparation activities may include
C-DAS customisation and visual inspection of internally and externally fitted
C-DAS equipment.
Traffic Regulation with C-DAS
3.8.1
C-DAS must enable the Traffic Management System to monitor the location and
speed of C-DAS fitted trains in the ROC area.
3.8.2
In the event that a C-DAS fitted train in a Controlled area cannot meet the arrival
time at a point on its current schedule, C-DAS must provide the Traffic
Management System with a predicted earliest possible arrival time at that point.
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GN126
3.8.3
C-DAS must provide the Traffic Management System and / or ROC staff with
information about the operational state of C-DAS on trains in the ROC area (see
Assumption 2.2.3.11).
3.8.4
C-DAS must confirm to Traffic Management when any C-DAS fitted train in the
ROC area has received a schedule update.
GN127
3.9
The predicted time will be a best-case estimate based on a partial view, since
the C-DAS will have no information about signalling, other trains or regulating
decisions.
These are applicable whenever C-DAS is operational, i.e. unless it has been
disabled.
Driving Policy, Guidance and Training
3.9.1
The RU must review its driving policy as part of the introduction of C-DAS.
3.9.2
Drivers’ competency and skills on the usage of C-DAS must be adequately
developed through the provision of suitable training and the definition of driving
guidance.
GN128
The RU is responsible for the training of staff who are directly involved with
the use, maintenance and preparation of trains which are fitted with C-DAS.
GN129
The following are factors that should be covered in the guidance and training:
3.9.3
GN130
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a)
Train preparation activities and any amendments to existing train
preparation task sequencing as a result of the introduction of CDAS.
b)
C-DAS customisation and setup before and during a journey.
c)
Driver handover procedures.
d)
Information display and controls.
e)
The status of the C-DAS advisory information and customisation
data displays.
f)
When to use C-DAS.
g)
Where C-DAS works, including which routes or parts of route are
in Controlled areas.
h)
Selecting current running line.
i)
When to manually suppress/unsuppress the C-DAS display.
j)
When to manually disable C-DAS.
k)
C-DAS fault reporting.
l)
System maintenance tasks.
The RU must decide the policy for C-DAS usage by its drivers.
The policy should reflect the understanding of the IM’s interest in drivers
following advice to support traffic regulation.
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GN131
Information provided to drivers by C-DAS is considered to be wholly advisory,
but if not following this information could have negative consequences for
drivers the status of the information will need to be defined by the RU in
consultation with driver managers and drivers.
GN132
The policy should include provision aimed at preventing drivers becoming
over-dependent on the C-DAS. Particular risks which could result ([RD9])
include:
Network Rail
a)
The erosion of driver route knowledge,
b)
Drivers prioritising C-DAS indications of TSRs and ESRs over
lineside signage.
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3.10
RU Roles and Responsibilities
3.10.1
General
3.10.1.1
The roles and responsibilities specified in this section are based on the use
case interactions outlined in Figure 1 below.
Figure 1 - System Boundary and Use Case Interactions
3.10.1.2
3.10.2
The responsibilities listed below are in addition to / clarification to those
already placed by ROGS.
Customisation Data Responsibilities
3.10.2.1
The RU must prepare and maintain all user data (see section 3.5.1 of this
document).
GN133
The decision on which items to display may utilise a suitable risk based
approach and should consider, for example:
a)
Whether information of a similar nature is already presented via
other systems.
b)
Whether the information supports driver operations.
c)
The impact of providing large amounts of displayed information
on the driver (is it readable, is it distracting), the physical size of
the display required, etc.
3.10.2.2
The RU must prepare and maintain all train specific data (see section 3.5.1 of
this document).
3.10.2.3
The RU must provide IM Operations Planning with the train specific
customisation data, in accordance with data requirements (for example
precision and granularity) agreed with the IM, to allow the performance of CDAS fitted trains to be modelled for the identification of network performance
improvements.
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3.10.2.4
The RU must ensure that all the user and train specific data required for CDAS operation is current.
GN134
This would include both maintaining train performance data values, and
ensuring that current data is made available to the systems from which CDAS will obtain it, e.g. ensuring that updates to train consist information are
delivered in a timely manner to the appropriate off-train system(s).
3.10.2.5
The RU must ensure that all data preparation and formatting processes
employ a level of checking appropriate to the required integrity of the data.
3.10.2.6
The RU must ensure the security of stored data and of the transfer of that
data for which it is responsible.
3.10.2.7
The RU must manage the transfer of the required datasets in sufficient time to
ensure that they can be made available to C-DAS onboard systems.
3.10.2.8
The RU must provide the IM with requirements for application datasets,
including data partitioning requirements where relevant.
3.10.2.9
The RU must manage any (RU maintained) local copies of application
datasets.
3.10.2.10
The RU must ensure that all the application data required for C-DAS
operation is correctly prepared and formatted.
GN135
The preparation of C-DAS application data once received from the IM may
include:
a)
Constructing gradients from altitude data
b)
Applying smoothing algorithms to gradient and curvature data
c)
Converting application data format.
3.10.2.11
The RU must ensure that any system requirements for validating onboard
copies of datasets are allocated to the appropriate RU operation and
technical systems.
3.10.2.12
The RU must ensure that correct versions of the application datasets are
available to the C-DAS onboard systems.
GN136
This will involve:
3.10.2.13
Network Rail
a)
Processes to ensure that current versions are obtained from the
IM and made available to the C-DAS onboard systems (see
clause 3.11.2.3);
b)
A check during Setup that the current versions are available to
the C-DAS onboard system (see clause 3.5.3.5)
The RU must ensure that the process for correctly preparing, formatting and
transferring application data to the C-DAS onboard subsystem limits the
amount of manual data entry. Where data is manually entered a checking
process appropriate to the required integrity of the data must be employed to
ensure the data is entered correctly.
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3.10.3
3.10.2.14
The RU must have contingency arrangements in place if any of C-DAS
software, application data and train specific data is not current.
GN137
Existing processes for the transfer of information between IM and RU, for
example those employed for the distribution of the daily applicable timetable,
timetable updates and TSR information should continue to be used where
possible, e.g. to support C-DAS setup in Uncontrolled areas. Contingency
arrangements may include, for example, requesting drivers to disable or
suppress the C-DAS onboard subsystem, and informing relevant operators.
3.10.2.15
The RU must develop the processes and procedures necessary for the
retrieval, analysis and distribution of C-DAS journey records.
GN138
The interval between retrieval of recorded data must be consistent with the
data storage capacity provided onboard.
3.10.2.16
The RU must develop processes and procedures necessary for the receipt of
system anomaly reports from drivers and/or maintenance staff. Managing
and addressing these reports may require co-operation with the IM.
3.10.2.17
The RU must develop and manage processes and procedures for the
maintenance and upkeep of the C-DAS onboard subsystem equipment and
interfaces, and any RU managed trackside equipment required to support CDAS operations in accordance with defined processes and procedures, to
meet system-wide availability targets.
Driver
3.10.3.1
3.10.3.2
3.10.4
3.10.5
a)
Complete system setup prior to journey start.
b)
Monitor C-DAS during the journey and follow the advisory information
in accordance with company driving policies.
c)
Amend or update setup information as required during the journey.
Where possible, drivers may also report any anomalies that are noticed in the
operation of the system, for example advised speeds higher than PSR.
Driver Manager
3.10.4.1
Where C-DAS is to be used, the Driver Manager must manage C-DAS driver
competency and arrange for drivers to be trained and/or briefed in the use of
C-DAS.
3.10.4.2
The Driver Manager must advise drivers if application data or train specific
data is not current or if software is faulty, so that the appropriate contingency
arrangements can be implemented.
Train Maintainer
3.10.5.1
3.10.6
The driver is the only direct user of the C-DAS on-train information, and must:
The train maintainer must perform C-DAS onboard subsystem maintenance
as required by maintenance processes.
Train Preparer
3.10.6.1
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The train preparer must complete any train preparation activities associated
with the C-DAS onboard subsystem.
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GN139
3.10.7
3.10.8
This could be carried out by dedicated train preparation staff or drivers.
Operations Controller
3.10.7.1
The RU must inform the IM when fleets are DAS fitted (S-DAS or C-DAS –
see Assumption 2.2.3.11)
3.10.7.2
The RU must inform the IM when drivers have been instructed not to use
DAS because of a software fault or because application data or train specific
data is not current.
Other RU Responsibilities
3.10.8.1
The RU must ensure that the software installed on the C-DAS onboard
subsystem is current.
3.10.8.2
Where practical the RU must provide the IM on request with selected journey
records (see 3.5.4) as inputs to capacity planning and timetable improvement.
3.11
IM Responsibilities
3.11.1
General
3.11.2
3.11.1.1
The roles and responsibilities specified in this section are based on the
interactions outlined in Figure 1 above.
3.11.1.2
The responsibilities listed below are in addition to / clarification to those
already placed by ROGS.
Customisation Data Responsibilities
3.11.2.1
The IM must prepare and maintain all application data (see section 3.5.1 of
this document).
3.11.2.2
The IM must define (and agree with RUs) options for specifying data
partitioning for application data.
GN140
Data partitioning might apply to all or any of Infrastructure Geography,
Permissible Speed, Applicable Timetable and TSR. Options could include, for
example, by route, operator or major area and also, in the case of speed
data, by train type.
3.11.2.3
The IM must define (and agree with RUs) configuration management and
operational protocols to be used by remote systems to ensure that versions of
datasets held locally or copied from local copies match the current master
version.
3.11.2.4
The IM must ensure that any system requirements relating to the use of these
protocols for validating datasets are allocated to the appropriate IM
operational and technical systems.
3.11.2.5
The IM must provide application datasets in line with the data partitioning
requirements specified by the RU.
3.11.2.6
The IM must disseminate complete, correct and accurate data in sufficient
time to make it available to IM and RU systems before they are required to
operate over the changed infrastructure, use the changed speed data or
operate to the changed timetable.
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GN141
This may require suppliers who update signalling infrastructure to provide
supplementary information with designs to identify potential impact of any
changes on DAS related data.
3.11.2.7
The IM must document and provide data access services to RUs.
3.11.2.8
The IM must ensure the security of stored data and of the transfer of that data
for which it is responsible.
3.11.2.9
The IM must ensure that any data preparation processes required for the
provision of application data or data updates employ a level of checking
appropriate to the required integrity of the data.
3.11.2.10
The IM must ensure that all the application data required for C-DAS operation
is correctly prepared and formatted in accordance, where relevant, with data
requirements (for example precision and granularity) agreed with the RU.
3.11.3
IM Data Preparer
GN142
The role of IM data preparer is responsible for collating, checking, and
maintaining C-DAS application data and delivering it to the RU. This role is
not necessarily fulfilled by one person, more likely a team of independent
preparers and checkers.
3.11.4
Signaller or Automatic Setting of Routes
3.11.5
3.11.4.1
The IM must determine, in conjunction with the RU, the policy for train
signalling and regulation control in areas where C-DAS trains operate.
GN143
Neither the signaller nor any system for automatic setting of routes is directly
involved with C-DAS. However C-DAS should reduce train speeds to prevent
early arrivals, which might require the signaller or route setting systems to
amend any assumed behaviours or rules used for determining how trains are
regulated (see Open Point 7 in section 4 and clause 3.8.3).
Other IM responsibilities
3.11.5.1
3.12
The IM must convey telecommunications requirements for the C-DAS
implementation to Network Rail Telecoms.
System Maintenance
3.12.1 The location of C-DAS system components must allow for easy access for all
required maintenance activities.
3.12.2 The C-DAS system must be fully testable in the maintenance environment.
3.12.3 The RU must consider the impact of DAS implementation on existing Vehicle
Maintenance Instructions (VMI) and Vehicle Maintenance Overhaul Instructions
(VMOI) and revise them as necessary.
3.12.4 The IM must consider the impact of DAS on existing maintenance specifications
and revise them as necessary.
3.12.5 Although not a CCS-type system, consideration should be given to including CDAS in existing DRACAS applications.
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Open Points
4.1
Overview
4.2
4.1.1
An open point is defined as an issue which requires further analysis or action to
resolve.
4.1.2
A meeting held on 11 March 2013 as part of the cross-industry review of an earlier
draft of this document decided to close a number of the open points documented
in that earlier draft. For traceability this section retains the original numbering of
open points.
4.1.3
The sections below list the open points, original working assumptions, a summary
of the resolution and a list of the key affected clauses.
4.1.4
The working assumptions where still relevant are additionally documented in
section 2.2, Assumptions.
Onboard DAS Operations
Open Point 1
Train determining current running line
Is there a requirement for the train to be able to identify (and inform the onboard
C-DAS subsystem) which line it is on? If so, does it apply to controlled areas,
uncontrolled areas or both?
Phase 1 Working Assumption
A facility will be provided for the C-DAS onboard subsystem to determine where
the train is operating on a route different from the route for which advisory
information is being provided. This facility will be available wherever there are
diversionary routes on which the onboard DAS is required to operate, including
both controlled and uncontrolled areas.
Phase 2 Resolution
Phase 1 working assumption confirmed. Relevant clauses: 3.2.19 and GNs;
3.6.2.22 and GN.
Open Point 2
Information display in TSR and ESR areas
Is it necessary / helpful to the driver to indicate a current or approaching TSR or
ESR area, or to display only the advice speed if lower than the TSR/ESR?
Phase 1 Working Assumption
Where a TSR or ESR has been applied the C-DAS will display an advice (current
and approaching) speed only if it is less than the applicable TSR or ESR speed
value. If the calculated advice speed (current or approaching) is equal to or
greater than the TSR or ESR speed then the system may display an appropriate
message, for current and approaching advice, to be determined by the RU (for
example “TSR” or “ESR”). Drivers will be trained to recognise and ignore an
advice speed if it exceeds the speed value associated with an ESR.
Phase 2 Resolution
See Appendix B. Relevant clauses: 2.2.4.3; 3.4.1; 3.4.3 (heading); 3.4.3.3;
3.4.3.4 and GNs; 3.4.2.4 and GNs.
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Open Point 3
Driver indications of connectedness
Does the driver need (or would the driver benefit from) an indicator showing
whether or not the train is
a.
In a controlled area (i.e. an area where updates to schedule and/or speeds
could be received).
b.
In current communications contact with the trackside, i.e. able at receive
updates to schedule and/or speeds.
Phase 1 Resolution
Open point closed – the driver will be provided with an indication to show when the
C-DAS onboard subsystem is in communication with the Traffic Management
system. Relevant clauses: 3.4.5.1.
Open Point 4
Sudden advice changes
How does a Driver know when an amended schedule or other advisory information
has changed? In particular, are there circumstances in which the onboard DAS
could receive a schedule update which would result in an immediate (‘sudden’)
change to the advice it displays, and if so is there a requirement for the onboard
DAS to present such advice in a distinctive way in order to bring it to the driver’s
attention?
Phase 1 Resolution
Open point closed – the refresh rate of the displayed current advisory information
will be controlled and configurable by the RU.
Phase 2 Resolution
Open point reopened. Relevant clauses: 3.4.2.8 and GN; 3.4.2.5.
Open Point 5
Countdown timer at station
Should a countdown timer to the scheduled departure time from a station be
displayed to the Driver?
Phase 1 Resolution
Open point closed – The RU should decide on the policy on provision and use of
countdown timers at stations, and possibly only for Driver Only operation (DOO).
Relevant clauses: 3.4.3.2.
Open Point 6
Driver Acknowledgement
Does a driver need to acknowledge any messages on the C-DAS user interface?
Phase 1 Resolution
Open point closed – there is no requirement for drivers to acknowledge any
messages on the C-DAS user interface.
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Train regulation with C-DAS
Open Point 7
DAS status information available to Signaller / Dispatcher / TM system
What information does the Signaller / Dispatcher / TM system need about the
fitment and / or operational status of DAS on trains in its area?
Phase 1 Working Assumption
Operators and systems in the ROC will have a need to distinguish between the
following for each train in the area: C-DAS fitted and working; C-DAS fitted but not
working (i.e. disabled); S-DAS fitted; no DAS fitted.
Phase 2 Resolution
Phase 1 Working assumption confirmed. Relevant clauses: 2.2.3.11; 3.8.3.
4.4
C-DAS System issues
Open Point 8
Pre-loading of Infrastructure Geography, permissible speed (including PSRs)
and TSR data
What Infrastructure Geography, permissible speed (including PSRs) and TSR
data, if any, should be downloaded to an onboard C-DAS subsystem at or before
journey start?
Phase 1 Working Assumption
The Infrastructure Geography data, permissible speed (including PSRs) and TSR
data for the scheduled route and any likely alternative re-routing will be
downloaded to the onboard C-DAS system at or before journey start and stored
persistently.
The data will need to include a means (which the onboard C-DAS subsystem
could use) of matching the operating line and schedule to the correct parts of this
data.
Phase 2 Resolution
Working assumption confirmed (with minor wording change). Relevant clauses:
2.2.3.12, 2.2.3.13, to GN28 to 3.2.18, 3.5.3.4.
Open Point 9
Self-test & Failure behaviour
Is there a requirement for self-test, diagnostic monitoring, identification of internal
C-DAS errors, or display of received DAS errors by the onboard?
What is the system response to failures, what indications are drivers given of
problems, and what is the user’s response to failures (drivers, signallers,
maintenance staff, operations control (TOC and IM)?
Phase 1 Resolution
Open point closed - The ability to test the system and the response to any test
shall be determined by the RU and communicated to other RUs and the IM. There
will need to be some validation of the data to confirm the equipment status. There
needs to be a process to determine whether the on train equipment is working
through a Driver initiated test. It is likely that on train DAS will need to
communicate its status on demand. Relevant clauses: 3.2.21 and GN; 3.12.2.
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Open Point 10
Safety Integrity Level of C-DAS
An appropriate Safety Integrity Level (SIL) rating must be incorporated within the
system design to recognise the potential consequences of drivers being provided
with the incorrect advisory information.
Phase 1 Working Assumption
There are no requirements on the C-DAS system which cannot be met by a SIL-0
system.
Phase 2 Resolution
Phase 1 working assumption overturned by Safety Analysis [RD9]. Relevant
clauses: 3.2.24.
Open Point 11
Reinforce Public Mobile Communications
Would there be a lack of confidence in the system if the communications are not
good enough?
Phase 1 Working Assumption
C-DAS will use multiple communications service providers and negotiate
communications improvement at route level. Requirements for coverage should
be conveyed into NRT’s Business Plan for CP5.
Phase 2 Resolution
Phase 1 working assumption confirmed (with minor wording change). Relevant
clauses: 2.2.3.7; 3.11.5.1.
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Definitions
Abnormal Working
Where there is extreme loading on a part of the railway system. For example, this may be
the result of extended delays on one part of the service impinging on another.
An unforeseen or unplanned event, which does not have life threatening or extreme loss
implications; it also includes faults and failures external to C-DAS equipment.
Advisory
Recommended but not compulsory.
Advisory information
The C-DAS recommendation to the driver.
Applicable Timetable
The Working Timetable as amended at 22.00 on the day prior to the day of operation.
Application data
Part of Customisation data (qv).
Bi-Mode
Alternative methods of powering a train. This can be via a Diesel Engine, or by Electric
power supply.
Coasting (or the advisory information COAST)
The driver does not need to apply traction to meet the requirements of the schedule, but
can still apply traction if necessary. The driver must still brake to follow any restrictive
aspects.
Connected DAS
Connected DAS (C-DAS) is a driver advisory system which is capable of communicating
directly with the IM Control Centre to receive dynamic updates of schedule and/or routing
information and/or speed restrictions, and to feed back information of use to IM systems.
This system may also be capable of communicating independently with either the RU’s
own control centre and/or other control centres.
Controlled area
An area controlled by a Traffic Management system. Such areas will be capable of
supporting full C-DAS operation, i.e. systematic data exchange in near-real time-between
C-DAS-fitted trains in the area and the Traffic Management system.
Current Schedule
The currently planned sequence of named locations, corresponding times and path for a
single train service. The time specified will be arrival and departures for scheduled stops,
and passing times for non-stopping locations. The current schedule may contain the same
data as the planned schedule, or include any number of schedule updates.
Customisation Data
The data which determines the detailed operation of the C-DAS. It comprises four parts:
a)
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Application data – Infrastructure Geography, Permissible speeds,
TSRs and ESRs, Schedule
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b)
Train Performance Data – parameters which determine the behaviour
of a particular train, including train length, mass, maximum speed,
braking parameters, traction parameters, resistance coefficients
c)
Setup-data – Driver Id, TRN, consist, communications addresses
d)
User data – selection and parameterisation of operator defined
features.
Data Partitioning
Infrastructure Geography and Permissible Speed datasets change relatively rarely, and
the aim is to partition these datasets so as to provide RUs with the Application data
required for their routes (see definition of Customisation Data above), but without requiring
updates to be provided when there are changes only to parts of the national data which
are not relevant to their operations. Data partitioning may also be useful for targeting TSR
data (updated weekly) and Applicable Timetable (daily) from IM to RU.
Degraded Working
Method of Signalling Trains when the normal controls are unavailable.
Disable
Action by which the DAS on board subsystem is closed down, either by the driver or
automatically, in the event of a system failure, display frozen or as instructed by the RU /
IM.
ETCS Fitted Trains
A vehicle which has been fitted with Onboard ETCS Equipment.
ETCS Operating Level
The level of ETCS functionality within ERTMS.
European Train Control System (ETCS)
Interoperable system to provide train protection and in cab signalling.
GB Mainline Railway
GB Mainline Railway has the meaning given to it in the Railways and Other Guided
Transport Systems (Safety) Regulations 2006.
Grey Train
Trains not equipped with C-DAS, or on which the C-DAS equipment is not working, or with
which C-DAS trackside cannot communicate, or unscheduled trains.
Infrastructure Geography
The data which describes the topography and topology of the network infrastructure. It
comprises three parts:
a)
Track Geography – Track centre line, altitude and curvature.
b)
Rail Network Model(s) – Connectivity and Navigability, including
operational line names.
c)
Track Features – asset data, including location of points, stations,
location markers e.g. mileposts, tunnels etc.
It must also include:
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d)
Linkages (mapping) between (b) and (a).
e)
Linkages (mapping) between Timing Point locations and track
geography / track features.
f)
Means (based on sequence of track link ID) to support mapping
between routing data and track geography.
Journey
The scheduled movement of a train between two named points, for example, journey
between London Euston and Glasgow Central.
Journey Segment
That part of the operational route which lies between adjacent timing points.
Linespeed
The Permissible speed modified by any applicable Temporary and Emergency Speed
Restrictions for a particular train type in the direction of travel.
Linespeed Profile
The Permissible Speed Profile modified by applicable Temporary and Emergency Speed
Restrictions to be observed by a particular train.
Network Model
A description of the track layout which specifies both its connectivity and how it may be
traversed, i.e. permissible sequences of track links.
Networked DAS
Networked DAS (N-DAS) is a driver advisory system which is capable of communicating
with a RU control centre or a collection of RU’s control centres without any direct input
from the IM. With this type of collaboration some of the benefits of C-DAS can be realised
within an Uncontrolled area.
Operational Train Number
The operational train identifier used by staff to verbally identify a given train service, and
unique to a service within a 24-hour period (TAF / TAP TSI definition).
Out of Course Operations
Where a train is diverted from booked route, has special stop orders, or where otherwise
defined in national rules and procedures.
Permissible Speed
(GE/RT8000-SP) The maximum permitted speed as shown in the Sectional Appendix.
This is the highest speed at which a particular train type may operate over a particular
stretch of infrastructure, and reflects infrastructure constraints, direction of travel and the
train type.
Plan
The collective schedule for multiple trains.
Planned schedule
The part of the Applicable Timetable that applies to a single train service. It is analogous
to the contents of the CIF [RD6].
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Route
The sequence of track links which make up the train journey or journey segment.
RT3973 Restriction
Condition of travel (including speed related, or restriction on route or line) which has to be
applied to a particular movement and is stated on form RT3973, Advice to Train Crew of
Exceptional Load.
Schedule
Same as Current schedule (qv).
Schedule update
Any change made to the Applicable Timetable in respect of a particular service so as to
accommodate VSTPs, regulate trains and/or recover from perturbation.
Setup data
Part of Customisation data (qv).
Standalone DAS
Standalone DAS (S-DAS) is a driver advisory system which has all customisation data
downloaded to the train at or prior to journey start.
Suppress
Action by which the DAS on board display is disabled in whole or in part. This is either
done by the driver manually or automatically in circumstances defined by RU / IM.
Timing Point
A timing point location in a train’s schedule, with an associated time qualified as arrival,
departure or passing time.
Timing Point Location
A location for which a time is specified on the train’s schedule. Timing point locations will
include all locations in the train’s published schedule, and may include further locations
which contribute to improving train regulation.
Track Link
The individual track between any two locations on a journey, subject to the limitation that it
cannot include any points, cross-overs or loops, other than as an end-point.
Train Performance Data
Part of Customisation data (qv).
Train specific data
Train Consist together with Train Performance Data.
Uncontrolled area
An area which is not controlled by an IM Traffic Management system. Such areas may
support N-DAS operation, i.e. limited data exchange between C-DAS fitted trains in the
area and an infrastructure facility.
User data
Part of Customisation data (qv).
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Working Timetable
The Working Timetable shows all train movements, their timings and other relevant
information. The WTT is revised on two occasions each year, the ‘Principal Change Date’
in December and the ‘Subsidiary Change Date’ in May.
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6
Abbreviations
ARS
Automatic Route Setting
ATOC
Association of Train Operating Companies
ATP
Automatic Train Protection
AWS
Automatic Warning System
C-DAS
Connected Driver Advisory System
CIF
Common Interface File (see [RD6])
DAS
Driver Advisory System
DfT
Department for Transport
DRA
Driver’s Reminder Appliance
DSD
Driver’s Safety Device
DVD
Driver’s Vigilance Device
EEDT
Energy Efficient Driving Technique
ESR
Emergency Speed Restriction
ERTMS
European Rail Traffic Management System
ETCS
European Train Control System
FOC
Freight Operating Company/Companies
GB
Great Britain
GN
Guidance Note
GRIP
Governance for Railway Investment Projects
GNSS
Global Navigation Satellite System
IM
Infrastructure Manager
ITPS
Integrated Train Planning System
Km/h
Kilometers per hour
Mph
Miles per hour
N-DAS
Networked Driver Advisory System
NRT
Network Rail Telecoms
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ORR
Office of Rail Regulation
OTN
Operational Train Number
PSR
Permanent Speed Restriction
RSSB
Rail Safety and Standards Board
ROC
Railway Operations Centre
ROSCO
Rolling Stock leasing Company
RU
Railway Undertaking
S-DAS
Standalone Driver Advisory System
TMS
Traffic Management System
TOC
Train Operating Company
TOPS
Total Operations Processing System
TPWS
Train Protection and Warning System
TRN
Train Running Number
TSDB
Train Service Database
TSR
Temporary Speed Restriction
UTC
Coordinated Universal Time
V/TC&C SIC
Vehicle/Train Control and Communications System Interface Committee
VTSP
Very Short Term Planning
WON
Weekly Operating Notice
WTT
Working Timetable
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Appendix A System Concept Architecture
A.1
Overview
A.1.1
A.1.2
A.1.3
A.1.4
Figure A.1 and the following sections present an overview of an example C-DAS
concept architecture, that is, a logical architecture not a potential implementation
scheme. Its purpose is to describe data flow and system/user interactions, but
organisational boundaries and interfaces are not included,.
The C-DAS concept architecture consists of an onboard subsystem, and a
trackside subsystem connected by a communications link. In this example
architecture the communications link between the onboard and trackside
subsystems is a wireless mobile link so as to reduce the dependence on physical
interfaces, including plugs, cables and sockets, and the associated failure
modes, and thus to enable data transfers at locations other than where these
physical interfaces could be provided.
In this example it has been assumed that:
a) The RU requires drivers to enter a Driver ID.
b)
All customisation data is transmitted to the C-DAS onboard subsystem via
the C-DAS onboard/trackside communications link.
c)
Journey records are held by the C-DAS onboard subsystem and transmitted
via the C-DAS onboard/trackside communications link.
In Figure A.1:
a) C-DAS system architecture elements are shown as red boxes.
b)
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The flow of data between the C-DAS trackside and onboard subsystems is
indicated by:
i)
Orange lines for data flow from trackside to onboard.
ii)
Purple lines for data flow from onboard to trackside.
c)
Onboard elements and interactions are shown within a blue border.
d)
Trackside elements and interactions are shown within a dark green border.
e)
Process and subsystem interactions are shown as black lines.
f)
Data flows for onboard journey recording are shown as green lines.
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Figure A.1 : Example C-DAS System Concept Architecture
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A.2
C-DAS Onboard Subsystem
A.2.1
A.2.2
A.2.3
A.2.4
A.2.5
A.2.6
A.3
The C-DAS onboard subsystem is a computer based system which monitors
progress of the train against the current schedule and provides advisory
information to the driver.
The C-DAS onboard subsystem is composed of the following:
a)
A navigation system to provide:
i)
Train location.
ii)
Train speed.
iii)
Time.
b)
A user interface.
c)
A processing unit.
d)
Interfaces to other onboard systems.
e)
An onboard communications link component
The onboard communications link component allows for the initiation,
maintenance, and termination of a communications link with the trackside
subsystem for the purposes of data exchange.
The onboard navigation system – typically a Global Navigation Satellite System
(GNSS) receiver – provides train location, speed measurement, and time
functions, all within the tolerances required for effective C-DAS operation.
The user interface provides the interface for all user interactions with the C-DAS
onboard subsystem, with the exception of manual C-DAS onboard subsystem
isolation and/or power isolation interfaces.
The processing unit controls and oversees all aspects of onboard C-DAS
operation:
f)
Initiates, manages and terminates a communications link with the offtrain C-DAS subsystem.
g)
Stores and manages changes to data received from the off-train CDAS subsystem and from driver input, and determines the relevant
working data (see section A.4 of this document for data descriptions).
h)
Processes all user inputs from the user interface.
i)
Processes inputs from other onboard subsystems.
j)
Calculates the advisory information to be displayed via the user
interface using predefined algorithms, onboard ‘working’ data and
real-time train location, speed and time data.
k)
Manages system status and operational states.
C-DAS Off-train Subsystem
A.3.1
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The C-DAS off-train subsystem is composed of the following:

An off-train communications link component.

An off-train data store.

Interfaces to traffic management
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
A.3.2
A.3.3
A.4
Interfaces to other off-train systems.
The off-train communications link component allows for the initiation,
maintenance and termination of a link with the C-DAS onboard subsystem for the
purposes of data exchange.
The C-DAS trackside subsystem can establish a connection with the C-DAS
onboard subsystem at any time for the purposes of journey data interrogation
only. The trackside data store is a managed store of customisation data required
for C-DAS operation. A description of the data held with the off-train data store is
provided in section A.4. Regulatory schedule, routing and speed restriction
updates are provided by the Traffic Management system where available.
C-DAS Data
A.4.1
A.4.2
A.4.3
Network Rail
The example architecture shown in Figure A.1 defines the following:
a) The different data sets that are required or generated for and by the C-DAS
system for each journey.
b)
A description of what information the data sets might contain.
c)
Where the information is sourced from and how the information is made
available to the C-DAS onboard subsystem.
d)
How the data sets are used.
There are eight data types associated with this example C-DAS architecture:
l)
Application
m)
Train specific
n)
User
o)
Driver ID
p)
TRN
q)
Stopping Pattern
r)
ESR
s)
Journey Record
The data types are associated with a data description as follows:
a) Static – data that is changed or amended infrequently, though it may be
refreshed at intervals (typically once or twice per year).
b)
Transient – data that may be changed or amended on a regular basis
(typically daily or weekly).
c)
Working – The data set utilised by the C-DAS onboard subsystem for a
particular journey.
d)
Dynamic – advisory or system status information presented by the onboard
DAS system to users via the user interface.
e)
Log – recorded operational data associated with a particular journey and a
particular driver that is made available for post-journey analysis.
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Appendix B Open Point 2: C-DAS display in TSR and ESR
areas
B.1
Problem statement
B.1.1
Is it necessary / helpful to the driver to indicate a current or approaching TSR or
ESR area, or to display only the advice speed if lower than the TSR/ESR?
B.2
Analysis
B.2.1
Introduction
B.2.1.1
Advising the driver of a current or approaching TSR was specified in the S-DAS
Operational Concept [RD5] in order to mitigate the risk of a driver misinterpreting the removal of speed advice at the start of a TSR as advice to drive
at full line speed. It was further proposed that the DAS should not advise a
speed value. The primary reason for this was the principle that an advisory
system should not display safety-critical information, especially since it would not
be possible, other than at prohibitive expense, to guarantee that the information
would be correct. Displaying the TSR speed was also seen as undesirable
because it could potentially tempt drivers to rely more on the DAS and less on
their route knowledge.
B.2.1.2
However there is also a (minority) opinion in favour of displaying the TSR or ESR
speed, based on the perceived usefulness of displaying contextual information
as a driver aid. Given also that drivers would be aware that the DAS would
sometimes present incorrect TSR or ESR information, the risk of dilution of route
knowledge would be low, and indeed drivers would be on the alert to spot
occasions where the DAS speed value differed from the speed value on the
lineside boards. In such cases drivers would know to ignore the DAS advisory
information, or indeed could use the manual suppress facility to suppress it.
B.2.1.3
It was decided to discuss the question of DAS display in TSR and ESR areas at
a DAS Cross-Industry Simulation Workshop held in London on 25 June 2014.
The discussion would take place in the light of a substantially increased amount
of industry experience, albeit still only with S-DAS, in the interval since [RD5]
was published.
B.3
Discussion
B.3.1
TSRs
B.3.1.1
For the driver the authoritative ‘version’ of a TSR is what is shown on the lineside
boards; any information displayed by the DAS (or indeed in the published WON)
is viewed as secondary, and training will ensure that it will be ignored if / when it
conflicts with the lineside boards.
B.3.1.2
The version of TSR information used by the DAS is derived from a computer file
containing a digital version of the WON data and there are currently no
processes to ensure that the lineside boards and this file are harmonised.
B.3.1.3
Nevertheless in practice TSR information in the DAS is generally complete and
correct (i.e. agrees with the lineside boards far more often than it disagrees)
though discrepancies certainly occur: daggered TSRs, TSRs cleared sooner than
planned, boards missing, incorrect speed values, mismatch of information in the
NR TSR electronic feed and the varying TOC DAS Systems’ route data, etc.
Such discrepancies will continue to occur in the future, though over time
improved procedures may be expected to reduce their frequency. Moreover
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lineside boards will be eliminated altogether in areas where all trains and the
infrastructure are ETCS-fitted.
B.3.2
B.4
ESRs
B.3.2.1
For the driver the authoritative version of an ESR is what is shown on the
lineside boards once these are in place, or as notified by the signaller.
B.3.2.2
ESR data will be available to the DAS only if it has been entered into a system
which communicates with the DAS. In Connected Areas this will be the Traffic
Management system; in Unconnected Areas there may be an RU system with
this capability, but only if the RU has chosen to operate an N-DAS system.
B.3.2.3
Even in a Connected Area ESR data may not always be available to the on-train
DAS subsystem, both as a result of delays in inputting ESR data to the Traffic
Management system, and communication delays in delivering it to the train. In
an Unconnected Area the same reasons will apply, even where the RU has the
capability to input ESR data.
B.3.2.4
Thus in practice it cannot be assumed that the DAS will mostly have current and
correct ESR data.
Conclusions
B.4.1
B.4.2
Network Rail
The following principles have emerged from the discussions at and following a
Workshop held on 25 June 2014:
– There is a clear (conceptual) distinction between Customisation data (as
defined in section 5above), which is the data available to the on-train DAS,
and DAS Advisory information, which is the advice generated by the DAS.
– Displaying elements of the Customisation data may support the driver in
making decisions, or may mitigate risk, or it may solely provide context.
– Display preferences are likely to differ markedly between different RUs and
routes.
– It is highly desirable that driver operation with C-DAS should be the same in
Controlled and Uncontrolled areas.
Applying these principles in respect of Customisation data in the context of DAS
display for TSR and ESR areas:
– The Linespeed profile (see section 5 above) for the route ahead is useful to
the driver as general context, by showing the data that the DAS is currently
using for its calculations.
– Indications of TSRs are useful to the driver to mitigate risk (by reinforcing the
driver’s route knowledge).
– Indications of ESRs are useful to the driver both to mitigate risk, by
reinforcing the driver’s route knowledge if the data is present in the on-train
system, and by aiding the driver in decision-making if it is not. In the latter
case, it will enable the driver to distinguish between the following, enabling
him/her to decide where DAS Advisory information should be followed:
o
DAS Customisation Data not already known to the driver, e.g. schedule
update, boarded ESR; in such cases the driver should follow DAS
Advisory information;
o
Driver knowledge not available to DAS, e.g. change to stopping
pattern, TSR where lineside signage differs from published details, new
(not yet boarded) ESR; in such cases the driver should discount DAS
Advisory information where it conflicts with own knowledge.
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B.5
Recommendations
B.5.1
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The following recommendations reflect the discussions at the workshop modified
by subsequent discussion and analysis:
1. The DAS display should enforce a clear distinction between DAS
Customisation data and the Advisory Information generated by the DAS.
2. “TSR” or “ESR” should be displayed as part of DAS Customisation data
wherever applicable.
3. If there is sufficient space on the display, the Linespeed profile for the train
type – for a distance ahead to be specified by the RU – should be displayed
as DAS Customisation data. This enables the driver to spot easily any
discrepancies between WONs and DAS data at a distance, or between
lineside boards and Customisation data at the TSR / ESR location.
4. In an area where there is no TSR or ESR it should be the RU’s decision
whether to display an Advice speed value only if it is strictly less than the
lesser of Permissible Speed and Maximum Train Speed, or also if it is equal
to this value.
5. In a TSR area the TSR speed value should be displayed, using the same
rule – in respect of ‘strictly less than’ or ‘less than or equal to’ – as for
Advice speeds in areas where there is no TSR or ESR.
6. In an ESR area the ESR speed value should not be displayed as an Advice
speed, and the display should indicate why no Advice speed value is
offered. In circumstances where ESR data becomes dependably available
to the DAS, the RU may decide to display the ESR speed, using the same
rule as for TSRs (see previous para).
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