FACTSHEET
Date
: 22 June 2015
Subject: GAUTRAIN SIGNALLING SYSTEM
The Operational Control Centre (OCC) located at the Gautrain Midrand depot controls all
train movements, the monitoring and control of the bus feeder system and key station and
tunnel equipment.
The signalling solution comprises Bombardier’s CITYFLO 250 system which is a fixed block
signalling system based on ‘distance to go’ principles with vital information being transmitted
to the on-board Automatic Train Protection (ATP) system from balises in the track. The ATP
supervises the driver and train movements.
System Functionality Overview
The CITYFLO 250 system is made up of three essential sub-systems:
o
Computer Based Interlockings (CBI);
o
the Centralised Traffic Control System (CTC);
o
Automatic Train Protection (ATP)
Computer Based Interlocking (CBI)
A total of six new EBI Lock 950 interlocking systems are being supplied in a distributed
arrangement throughout the alignment, with a seventh interlocking system provided for
depot signalling at the Operation Control Centre (OCC). A field engineering unit (FEU) is
provided with each interlocking as a maintenance support tool.
EBI Lock object controllers located at each station equipment room, as well as a number
along the alignment, are the interface between the computer based interlocking and the
wayside signalling system, comprising:o
Train Detection,
o
Control of Switches (turnouts),
o
Optical Indication, and
o
Track (Balise) to Train Transmission
Centralised Traffic Control (CTC)
Traffic supervision and control is made possible through the CTC located at the OCC depot.
An EBI Screen CTC system is provided for this purpose. EBI Screen has a graphical
man/machine interface using a Windows-based operating system. Views of the controlled
process are shown on video display units, with abnormal alarming situations indicated to the
operator by means of visual signals. (Alarms are assigned different priorities.)
The main function of the CTC is to support the operational personnel with all operationrelevant information and processing of their requests during operational situations.
The supervision and control of the signalling field elements is based upon the data exchange
between the CTC and the EBI Lock interlocking, and the system has an authority-based login
which ensures that operators will interact only with objects belonging to their corresponding
authority areas.
Trains are followed through all tracks in both the main lines and the depot. Train descriptions
follows track occupancy on the mainline.
Train descriptions are produced by the train
describer system. The train describer system of the CTC produces train descriptions based on
train detection information received from the signalling system Interlocking and compares the
train positions of the timetable.
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Manual commands are available for CTC operational personnel, but route setting is normally
automatic, based on timetables.
Signalling
EBI Lock interlocking systems provide the integrity to protect train movements as required by
the timetable or by operator command. The interlocking system accesses commands from
the operator, status indications from the wayside through the object controllers and, once the
correct conditions are fulfilled, allows a route to be signalled.
Commands can be automatic from the timetable system, the CTC operator, the emergency
local control operator.
Two-aspect signalling provides a visual indication of the status of the route indication to the
driver. When presented with a proceed aspect, the driver is permitted to drive the train
through the route. Controlled balise groups protect the route at the signals. Depending on the
condition of the route, the interlocking will transmit a message (“telegram”) to the balise
group that can then be tele-powered by the compact antenna on the train. In the event of
a failure in communications between the balise group and the balise interface card, the
balise group uses the programmed default telegram.
The default telegram for the controlled infill balise group is movement authority to the next
signal only with the balise group configured as a ‘repeat signal’. The default telegram for the
balise group at the signal is an error telegram programmed as ‘absolute stop’. The train brakes
to a halt and an onboard ATP mode change to ‘pass stop’ On receipt of a valid telegram
containing a movement authority, the train ATP will provide permitted speed and distance
information to the driver. If the telegram is “stop”, the train is braked to a halt. If the default
telegram is being transmitted, the train records the error and supervises the train to the last
valid movement authority inserted.
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Fixed balise groups (not connected to the Interlocking) are provided for datum reference
purposes and updates of the static speed profile. Controlled infill balise groups are provided
before the braking points are located at the end of routes so that the train receives the next
movement authority and continue at maximum permitted line speed.
Onboard Automatic Train Protection (ATP)
The ATP is a safety-critical system that continuously supervises the movement of the train. It
warns the driver in case of over-speeding and when approaching stop signals or changes to
the static speed profile. If the driver does not reduce speed sufficiently, the system orders the
vehicle to apply brakes. This means that the ATP system does intervene as long as the driver
drives below the permitted speed and stops before signals in ‘stop’.
In order to perform the supervising functions, the ATP system receives information from the
balise, such as speed restrictions, distances and gradients. The ATP is a continuously
supervising system using intermittent updating, which means that the speed is continuously
supervised but the information is given to the vehicle at ‘information locations’. An Information
Location (IL) consists of two balises mounted in the track. An antenna unit (CAU, Compact
Antenna Unit) mounted underneath the vehicle sends an “activation signal” towards the
ground as long as the vehicle is moving. When a balise receives this signal, it responds by
transmitting an IL telegram, containing necessary track information.
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The ATP system is designed for a maximum train operational speed of 160kph. The design
recognises that the train can go faster before an ATP intervention occurs. The interlocking
provides movement authority information to the train (via the balise groups) that allows the
train to calculate and supervise a smooth and gradual brake to the target restriction.
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