Page 567 - IRSEM_Main Book

Communication-based train control (CBTC) is a railway signaling system that makes use of
the telecommunication between the train and track side equipment for the traffic
management and infrastructure control. By means of the CBTC systems, the exact position of
a train is known more accurately than with the traditional signaling systems. This results in a
more efficient and safe way to manage the railway traffic. Metros (and other railway
systems) are able to improve headway while maintaining or even improving safety.

IEEE 1474 standard defines CBTC as a "continuous, automatic train control system utilizing
high-resolution train location determination, independent from track circuits; continuous,
high-capacity, bidirectional train-to-wayside data communication; and trainborne and
wayside processors capable of implementing automatic train protection (ATP) functions, as
well as optional automatic train operation (ATO) and automatic train supervision (ATS)
functions".

CBTC applicability:

 Mainly suitable for urban railway lines (either light or heavy) and APMs (Automated people
mover)
 Also deplorable on commuter lines/suburban lines.
 For main lines, a similar system of ERTMS (Level-3) exists, though it is not yet fully defined.

CBTC systems in India

Metro Make

Kochi Metro Alstom
Hyderabad Metro Thales

Lucknow Metro Alstom

Delhi Metro Line-7 Bombardier

Delhi Metro Line-8 Nippon

Noida Metro (operated by DMRC) Ansaldo

Nagpur Metro Siemens

Ahmedabad Metro Nippon

CBTC Functions:

 The trains continuously calculate and communicate their status via radio to the wayside
equipment distributed along the line.
 This status includes, among other parameters, the exact position, speed, travel direction
and braking distance.
 This information allows calculation of the area potentially occupied by the train on the track.

 It also enables the wayside equipment to define the points on the line that must never be
passed by the other trains on the same track.

Annexure G3: CBTC in Metro Railway Systems Page 510 of 535