Tehran Metro L7 – Project Summary
Information
Tehran Line 7 covers an approximately length of 26.46 km in a South-East/North direction with 22
underground stations. A7, B7, D7, E7, G7, H7, I7, J7, L7, M7, N7, O7, P7, Q7, R7, S7, T7, U7, V7, W7, X7, Y7. The design
length of all the platforms is 160m. A ground level workshop is located in South-East end associated with a main
parking area for 40 (8-car train) trains.
Introduction
The CITYFLO 350 solution comprises several integrated subsystems in order to provide a safe, reliable and efficient
signalling system with high availability.
There are four main system levels
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Wayside equipment: Computer Based Interlocking system (EBI Lock 950 CBI) including OCS950 object
controllers, as well as wayside objects (such as EBI Track audio frequency track circuits, EBI Light optical
signals or EBI Switch point machines)
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Onboard equipment: EBI Cab vehicle ATC equipment including both ATP and ATO functionality, plus
other support systems such as the vehicle radio equipment part of the TWC sub-system
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Supervision equipment: EBI Screen CTC and Local Control systems, including the Wayside ATO (WATO)
functionality.
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Communications: This level comprises both the Train to Wayside Communication (TWC) system based
on radio links, as well as the different Data Transmission Systems (DTS) which are the communications
networks based on fibre optic media and used to communicate the wayside equipment
Within this architecture, the onboard equipment provides the solution with ATP (speed supervision) and ATO
(acceleration, braking and precision braking) functionalities. The ATP information is transmitted from the wayside
equipment by means of the track circuits, while the ATO information is transmitted between the train and the CTC
via the TWC link. The CBI keeps track of all the train locations (occupancies), the status of signals, point machines,
routes, etc. and provides ATP information to the trains over the track circuits.
Wayside subsystems and supervision subsystems such as the CBI and the CTC (including its WATO module) are
interconnected using communication networks (referred to as Data Transmission Networks, DTS)
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On one hand, the signalling network used inside the CBI architecture (for communication with OCs or
between adjacent interlockings) is completely dedicated and comprised by redundant data transmission
systems.
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On the other hand, another data transmission system (ATC DTS) is deployed for the TWC communication
architecture in order to communicate the CTC with the trains for the ATO functionality.
CITYFLO 350 system consists of Automatic Train Protection (ATP) system EBI Cab, an onboard Automatic Train
Operation (ATO) system and an integrated operation control centre in combination with the distributed electronic
computer based interlocking (CBI) system. EBI Lock interlocking detects track circuit occupancy with the help of
track circuits and gives movement authorities to the onboard EBI Cab equipment that works with the ATP
supervision based on “Distance to go” principle.
Computer Based Interlocking (CBI)
EBI Lock Computer Based Interlocking system ensures maximum availability and safety by the use of dual
interlocking computers (VCS_R) and diversified software. The interlocking system is of a modular design for high
flexibility, and is easy to adapt to different interlocking principles.
EBI Lock is an Electronic Interlocking System. It consists of a central interlocking computer and an Object Controller
System (consisting of object controller cabinets) as well as a local control workstation and test facilities at each
interlocking location.The Computer Based Interlocking System (CBI) checks that all conditions for authorizing train
movements and other operations in the Railway regulations are met. CBI is placed in Signalling Equipment Rooms
in the designated Interlocking Stations.
Point machines, Signals, Track circuits and other vital functions will be interfaced and controlled by object
controllers. The object controller cabinets are placed in the Signalling Equipment Rooms. A Local Control
workstation is used to monitor the status of wayside equipment and includes a maintenance terminal for
monitoring and handling alarms from the interlocking computer and object controller system.
Object Controller System (OCS950)
The Object Controller System (OCS) will be installed at every station along the line in the equipment room
and controlled by the interlocking (EBI lock) via the fiber optic.
OCS is an integral part of the EBI lock computer based interlocking. The OCS represents the part that
controls and monitors the states of various wayside objects of both failed-safe and non-failed-safe nature.
The object controllers are connected to the central interlocking computer by a number of loops. Each loop
is a transmission line that can serve several concentrators. The loop concept provides the ability to
communicate from two directions on the line, ensuring availability even in the event of cable failure. Each
concentrator has connections for up to eight object controllers. Each object controller, in its turn, controls
and monitors one or more wayside objects (signal, point, etc.) using microprocessors specially
programmed for the interface
The object controllers were installed in the station buildings which provides a safer working environment for
maintenance, and gives better control of the environment thus helping to increase reliability. The vital transmission
between the central interlocking computer and the object controllers is made in closed transmission loops that
retain communication to every controller in the event of a fault in the transmission equipment or cables.
Local Control
EBI Screen system is placed at each interlocking station in the line for the control of points and indication
purposes. EBI Screen supplies a Man-Machine Interface (MMI) to the interlocking. EBI Screen runs on a standard PC
platform, in the Windows operating system environment.
Coded Audio Frequency Track Circuit (TI21-M) for the Main Line
Coded Audio Frequency Coded Track Circuit is operated in two modes
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Train detection mode, the purpose is to decide if a train is present in the track area or not
Telegram sending mode, the purpose is to send information from the CBI to the ATP via the
OCS
The track circuit (TI21-M) is of the Audio Frequency joint less type, designed for use in AC or DC
electrified areas where high levels of interference may be present.
Electrical separation between track circuits is normally being provided by tuned areas of track. However TI21-M
must be used in jointed mode through point work. As well as providing safe train detection, TI21-M can also be used
to transmit data to the train in an occupied section. This data is fed to the transmitter via a serial link from an Object
Controller which provides ATP encoded data
The EBI Track audio frequency track circuits allow speed values, distances, gradients and other information to be
transmitted to trains. The TI21 type Metro track circuit needs no insulated rail joints (IRJ) in straight-line track.
TI21-M track circuit (coded) is used for the main line and the depot test track. The TI21-M uses a carrier wave in
the audio frequency range enabling the use of digital modulation with a high data bit rate. This enables onboard
ATP to use distance-to-go supervision of the train's movements.
Point Machine
The AC type point machines shall be supplied used for electrical operation of single points, double slip
points and derailers, which provided by other supplier. OCS system will provide appropriate interface to the point
machines. The Point machine used for main line is the same with that for depot, which are AC point machine
ZDJ9.
Signals
The 3 aspects (red/yellow/green) signals has been provided in the Mainline while the 2 aspects (blue/white) signals
has be provided in the Depot.
Station Emergency Stop Push buttons (ESP)
If passengers at a station operate one or more platform emergency stop plungers then trains near that station shall
automatically be signalled to make an emergency stop. For the purposes of this requirement
a train shall be considered to be near the station, when any part of the train is alongside a platform of that
station or when the train is approaching the station and within braking distance of it. If other trains approach the
station before the emergency plunger operation has been cancelled those trains shall be
brought to standstill before they enter the station. The manner in which that signal is acted on shall be dependent
on the mode in which the train is being driven.
Automatic Train Protection (ATP)
A continuous coded track circuit based Automatic Train Protection (ATP) system EBI Cab with “Distance
To Go” principle will be implemented.
The system is designed to assist the driver in driving the train in the safest and most efficient way. It
provides relevant signal information in the cabin and continuous monitoring and supervision of the driver’s
action, train speed, distance to the restriction or hindrance and safe braking profile. The ATP system is
based on well- proven coded-track circuit technology.
The improved transmission technology and new electronic microcircuits that enable the more advanced
ATP supervision facilities. The old speed code systems, used widely in Metro applications, could only
transmit and supervise a few speed levels. In a distance-to-go ATP such as EBI Cab the train borne ATP
compares continuously the train’s actual speed and position with the safe speed profile, individually
calculated for each train. Advantages compared to a speed code system are the following
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EBI Cab onboard always brakes the train as late as possible, yet guarantees that it stays within
the safe speed profile and stops just before it reaches the point of hindrance
Every train may brake as late as possible with its individual braking capacity
Braking to stop can be done in one smooth deceleration without steps as in a speed code
system, also from high speeds
Smoother ride for passengers
Automatic Train Operation (ATO)
The Automatic Train Operation system (EBI Cruise), works along with ATP protection and has the
following major control functions:
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Acceleration, cruising and precision braking of the train based on information communicated
between the train and CTC via the TWC.
EBI Cruise ATO system will increase the passenger comfort with its control system.
Data variables that originate from Precision Stop Marker (PSMs) balise telegrams are received by the EBI
Cruise computer from the EBI Cab computer. The EBI Cruise also receives information from the
departure buttons and the EBI Cruise Track database with static information about the line.
The EBI Cruise computer can only be active when the EBI Cab computer allows and supervises
automatic driving from the starting point to the precision stop point
The driving strategy of the EBI Cruise can be optimized for either minimum travel time or minimum energy
consumption by using the phases of the Speed Control Function differently. This means that the
operational costs can be minimized and the traffic flow can be optimized, and controlled by driving
strategy decided by the control centre.
When the fast driving strategy is chosen, the ATO minimizes the travelling time between stations. The
speed levels permitted by ATP are fully monitored. The ATO accelerates the train with maximum possible
acceleration rate.
When the normal driving strategy is chosen, the ATO makes a compromise between on one hand short
travelling time and on the other hand low energy consumption. The maximum speed is 5 km/h lower than
in fast strategy. When the train has reached the maximum speed, propelling is interrupted and coasting
starts. If the train’s speed falls too low, the ATO will order acceleration again.
When the slow driving strategy is chosen, the ATO minimizes the energy needed for running the train
between stations. The maximum speed is 10 km/h lower than in fast strategy. When the train has reached
the maximum speed, propelling is interrupted and coasting starts. If the train’s speed falls too low, the
ATO will order acceleration again.
Responsibilities and Duties
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Conducting a Site survey of Signalling Equipment rooms civil works and to make ensure that works have
been implemented as per defined standards. This survey includes assessing structural integrity, electrical
installations, environmental conditions, and documenting any deviations or improvements needed
Completed and verified track chainages as per finalized signalling plan. This survey involves precise
measurement and alignment of distances along the track with the signaling components
Supervision of installed equipment including Cables, Tuning Units, Impedence bonds, Signals and Rail
joints and to make ensure that installation work is done as per described standards
Prepare daily work reports/ ITC handover reports, Red marking drawings and send to ITC Manager to
keep him updated
Testing of OCS950 cabinets, Tuning Units, Signals, Point machines and Emergency Switch plungers
Documentation of installed and tested equipment and to upload in Drive
Ebiscreen Workstation software installation guidelines and training to customer
Complete understanding of VCS_N software installation and its configuration
Correspondance and commissioning of stations after successful completion of testing
Training to customer regarding Troubleshooting of Object Controllers, Signals and Track circuits