Advanced Train Operation
PTC and CBTC
© American Public Transportation Association - 2015
Copyright Restrictions and Disclaimer
Presentation Author
Nicholas Columbare
Solution Director
Strategy and Solution Portfolio
ALSTOM
1025 John Street
West Henrietta, N.Y., 14586
585-279-1465
Nicholas.Columbare@ALSTOM.com
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© American Public Transportation Association - 2015
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Train Control Basic Objectives
B
A
Efficiently transport passengers / freight from point A to point B enforcing :
• Safety
• Train schedules
Under whatever the conditions:
∙ Traffic density to meet throughput needs
∙ Perturbations, failures, and degraded modes
© American Public Transportation Association - 2015
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Why is there a need for train control
• Environmental conditions, the mass of the train, and
increasing speeds make it more and more difficult to operate
safely without the assistance of technology.
Braking distance:
• If a car can stop in
75m (dry weather) at
90kph,
• a high speed train like
the ALSTOM TGV will
take 3200m at
300kph…
© American Public Transportation Association - 2015
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Train Control Signaling
• Signaling is fail-safe:
– “A fail-safe device is one that, in the event of failure, responds in a
way that will cause no harm to other devices or danger to personnel”
• Safety is ensured but there is a compromise between:
− System “fail-safe” capability
− Operating procedures (especially in case of signaling override and
manual operation)
• Safety measures are usually detrimental to traffic
performances, and must be balanced against system reliability
and availability.
© American Public Transportation Association - 2015
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Why Communications Based Train Control (CBTC)
and Positive Train Control (PTC)?
• Traditional systems in North America have been based on block signaling systems designed 30 100 years ago
• Technology for ETCS (European Train Control System functionally similar to PTC) has been
available since the 1990’s in Europe
• CBTC Technology was first deployed in Asia in the early 2000’s
•
CBTC and PTC systems can offer
improvements over block signaling:
Equivalent or better safety
Improved performance
Increased reliability
Higher system throughput & capacity
Improved schedule adherence & reduced
variability in system performance
© American Public Transportation Association - 2015
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Line capacity and Safe Braking Distance
• Line capacity is the maximum number of trains that can be transported on a line past a
fixed point during a set time period.
• A signaling system influences capacity by regulating
• Dwell time in stations
• Minimum train separation required for safety
• The minimum train separation is dictated by the safe braking distance of a train
• e.g. the distance needed to safely stop prior to a safety hazard
Rolling stock acceleration and braking performance
Maximum authorized train speed
Train detection granularity
Driver reaction time
Safe
braking
distance
© American Public Transportation Association - 2015
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Block Signaling
Block Signaling
without
Automatic Train
Protection (ATP)
• Movement authorities communicated via signals to driver
• Subject to human error / variability
• Safe breaking distances designed to worst case scenario not current conditions
Block Signaling
with cab signal
and ATP
• Movement authorities communicated via frequency pulse modulated signals through
track circuit blocks
• Fail-safe, onboard computers stop train within safety zone
• Safe distance between two trains will be the worst case braking distance based speed
Braking speed curve
SPEED CODE
Code 40/00 mph
Code O mph
00/00
Speed Code transmission
Track Circuit
Stopping point
Track Circuit
Track Circuit
© American Public Transportation Association - 2015
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Distance to Go and Positive Train Control
Distance to Go
• Movement authorities communicated based on track conditions ahead and civil speed
restrictions
• Fail-safe
• Permits precision stopping
• Eliminates overlap block behind each train
• Mandated by Law to reliably and functionally prevent:
• Train-to-train collisions
• Over speed derailments, including enforcement of:
• Civil engineering speed restrictions, slow orders, speed restrictions over switches
• Incursions into established work zone limits without appropriate authority
• The movement of a train through a main line switch in the improper position
Positive Train
Control
Distance to Go braking speed curve
60 mph
Target speed and distance
transmission
Track Circuit
Stopping point
Track Circuit
Track Circuit
© American Public Transportation Association - 2015
Reference: United States of America. Federal Railway Administration. January 5, 2011. U.S. Code Title 49: Transportation. Subpart I—Positive Train Control Systems
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ACSES – PTC on the North East Corridor
ACSES - Advanced Civil Speed Enforcement System
•
•
•
•
Enforces stops, permanent and temporary speed limits.
Uses braking profiles for warning and enforcement
Receives intermittent line data from transponders
Radio used for dynamic wayside system status updates
ACSES on the North East Corridor is currently applied as an overlay to a
block signaling system with cab signaled speed codes
•
•
•
•
Train detection (track occupancy logic)
Interlocking logic
Broken rail detection
Onboard enforcement of “signal” speed.
http://transportationfortomorrow.com/final_report/volume_3_html/05_field_hearings
/content19ab.htm?name=1106_newyork_presentation_panel2
© American Public Transportation Association - 2015
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Positive Train Control
Transponders
Communications Based (220Mhz TDMA Radio)
Onboard Controller
Central Safety Server
Wayside Interface Units
Interlocking (external system)
© American Public Transportation Association - 2015
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Architecture Overview
ACSES:
Onboard receives
precise location
data and civil
speed from
transponders.
Wayside Interface
Units and Safety
Server send
interlocking status
to Onboard via
data radio
Onboard enforces
limits and braking
profile
Dispatchers may
enter specific
speed restrictions
© American Public Transportation Association - 2015
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Transponder Transmission Subsystem
Positive
Train Stop
Target
Location
Data
Civil Speed
Restriction
Data
Address of
wayside
equipment
Transponder
© American Public Transportation Association - 2015
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Train to Wayside Communication
© American Public Transportation Association - 2015
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Vital Safety TSR Server to Manage Temporary Speed
Restriction Data:
TSR – Train Speed Restriction
© American Public Transportation Association - 2015
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PTC Interoperability Issues
High need for
interoperability
between
railroads which
operate on
territories with
diverse PTC
solutions
http://nec.amtrak.com/content/nec-and-connecting-commuter-rail-services
© American Public Transportation Association - 2015
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ACSES Technical Challenges on NEC
Implemented as
a mandated
safety system,
future system
optimizations?
Ongoing
implementation
of new radio
band (900 Mhz
to 220 MHz) and
communication
system
Evolving the
system to
incorporate new
products and
advancing
technologies
© American Public Transportation Association - 2015
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From Block Signaling to CBTC Moving Block
Braking speed curve
SPEED CODE
Code 40/00 mph
Code O mph
00/00
Stopping point
Speed Code transmission
Track Circuit
DISTANCE TO GO
Track Circuit
Track Circuit
Distance to Go braking speed curve
60 mph
Target speed and distance
transmission
Track Circuit
Stopping point
Track Circuit
Gain
Track Circuit
Moving Block braking speed curve
CBTC MOVING BLOCK
Movement Authority
80 mph
Stopping point
Protection Envelope
Additional Gain
© American Public Transportation Association - 2015
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Communication Based Train Control
Communication
Based Train
Control
• Per IEEE: System shall provide
• high-resolution train location determination, independent of track circuits
• continuous, high-capacity, bidirectional train-to-wayside data communications
• Automatic Train Protection (ATP) functions shall provide fail-safe protection against
• Collisions, excessive speed, and other hazardous conditions
• Automatic Train Operation (ATO) functions shall control basic operations within the protection
limits imposed by ATP.
Movement Authority precision is increased by absolute train detection envelope
Safe braking distance is based on current train speed and location
CBTC MOVING BLOCK
Moving Block braking speed curve
Movement Authority
80 mph
Stopping point
Protection Envelope
© American Public Transportation Association - 2015
Reference: IEEE Standard for Communications- Based Train Control (CBTC) Performance and Functional Requirements. IEEE Std. 1474.1, Page 1-28, 2005
19
© American Public Transportation Association - 2015
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ALSTOM URBALISTM – More than 25% of radio
based CBTC deployments worldwide
A leader’s experience in radio CBTC :
Today, Operators trust URBALIS radio CBTC for 49 metro lines
spanning driverless or manned systems, new lines or signaling renovation.
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Automatic Train Protection – ATP
Maximum
speed
Warning
curve
Emergency
Brake curve
120 km/h
Train Speed
(Manual Driving)
ATP = Supervision of Train Speed
0 km/h
If Train Speed >Emergency Brake Speed,
then Emergency Brake = ON
Else If Train Speed > Warning Speed
then Warning Sound = ON
End
© American Public Transportation Association - 2015
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Automatic Train Operation – ATO
Maximum
speed
Warning
curve
Emergency
Brake curve
120 km/h
Train Speed
(Auto Driving)
0 km/h
ATO = Drives the Train
Traction and Braking of the train is
not managed by the driver, but by the
ATO train equipment (Automatic Pilot)
ATO: reduces system variability while allowing
for power consumption optimization
© American Public Transportation Association - 2015
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Communication Based Train Control
Transponders
Communications Based (2.4, 5.8, 4.9 Ghz)
Onboard Controller
Centralized Zone Controller
Wayside Interlocking Control
Centralized Interlocking processor
© American Public Transportation Association - 2015
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CBTC General Architecture
ATS & SCADA
Interlocking
Controller
ATC
Zone Controller
PIS & Security
Maintenance
DCS – GIGABIT NETWORKS
RADIOS
ATC
Onboard
Controller
Interlocking I/O
PIS & Security
Station
PIS & Security
• ATS: Automatic Train Supervision
• PIS: Passenger Information System
• SCADA: Supervisory Control And Data Acquisition
© American Public Transportation Association - 2015
• ATC: Automatic Train Control
Zone Controller Moving Block Operation
Movement Authority
Direction of traffic
Train speed
Automatic protection
A
Movement Authority
•
•
The Zone Controller calculates
Movement Authority based on train
location and track database and
transmits it to the trains
Automatic protection
B
Braking curve
ATC
Zone Controller
Location
Train Y
…
Train B
Train A
…
Train X
•
Onboard controller calculates braking
curve and precise location
•
Trackside beacons
contain static
location information
In between beacons odometers
and high performance slip/slide
algorithms are used to calculate
location
© American Public Transportation Association - 2015
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Interlocking: the logic and the track product
information
Signal
Switch Machine
Interlocking
Controller
Conditions “out”
Track
Circuits
- switch machine move
- signal changes
Interlocking I/O
Conditions “IN”
Interlocking
(Logic)
- track circuit occupancy
- switch position
© American Public Transportation Association - 2015
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Control Center for decision support
Passenger information
ATS & SCADA
PIS & Security
Energy, Ventilation, Ancillaries
Security (CCTV,…)
Signalling
Train interface
Mass transit
Suburban
© American Public Transportation Association - 2015
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Security and Information
Integrated Security and
Passenger Information
Center
Visual travel
information
or emergency
messages through
displays
Audio & visual
information or
emergency messages
through WiFi
communication
ATS & SCADA
PIS & Security
People and assets
protection through
intrusion detection &
access control
Event detection,
monitoring
through video
surveillance
Fire Detection
Audio travel
information
or emergency
messages
through public
address
Emergency call
point/intercom
Audio & visual
information or
emergency
messages
through kiosk
© American Public Transportation Association - 2015
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Security and Information – Trainborne
PIS & Security
Audio Announcement
Video Surveillance
Passenger Information
Passenger Emergency Intercom
Infotainment/Advertisement
Internet
© American Public Transportation Association - 2015
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Data Communication System
Complete redundancy for robust availability
ATC
Zone Controller
Interlocking
Controller
ATS & SCADA
PIS & Security
Switch Router
Backbone
Redundant Backbone Transmission Network
Station 1
Redundant
Access Point
AP
AP
AP
AP
AP
Double Radio Cell
Station
AP
Double
Radio cell
400m to 1600m (*)
Station 2
AP
AP
AP
Optical
fiber
Double Radio Cell
© American Public Transportation Association - 2015
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Innovation in CBTC: Increasing the simplicity of the
system through train-oriented architectures
“Wayside-centric”
CBTC system
“Train-centric”
CBTC system
ATS
ATS
Route request
Object Controller
Interlocking
Block
status,
overlap
release…
Train movement
Location
Train movement
Zone Controller
Location
EoA
Train
Several information paths and models
to be reconciled
Train
Track resource request
/ release
Infrastructure
Controller
One consistent information path
-
No need to synchronize Interlocking and ATC
Design can be focused on headway, flexible
operation, and robust performance.
© American Public Transportation Association - 2015
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System Optimization
“Train-centric”
CBTC system
“Wayside-centric”
CBTC system
Location request
MA
Following
Vehicle
MA
Preceding
Vehicle
End of
Authority
ATC
Zone Controller
Locatio
n
report
Cyclic communication
with ATC Zone Controller
Following
Vehicle
Location
report
& commitment
Preceding
Vehicle
Train-to-Train communication
From System Theory
• A technical system throughout its life tends to
become more reliable, simple, and effective moving
towards a more Ideal state:
• Transfer functions to the working element
which produces the final action
© American Public Transportation Association - 2015
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Conclusions
• Advanced train control design and deployment requires a
multidiscipline effort to successfully balance safety,
performance, and system reliability.
• The increasing complexity of train control systems requires
an engineering community that can create holistic solutions
that match the magnitude of the challenges presented by
the transportation industry.
• Transportation solutions are a means of improving the
quality of life of people living in high density urban centers.
© American Public Transportation Association - 2015
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THANK YOU
© American Public Transportation Association - 2015