Tender invited for Development of Train Collision Avoidance System

ISO 9001: 2008 Effective from 18.06.2012 RDSO/SPN/196/2012 Version 3.1.1
Document Title : Specification of Train Collision Avoidance System
Communication from Station/ IBS/ Gate unit to Loco unit:
6.31. As soon as Station/IBS unit receives the information about the entry of a train in
the adjoining block section alongwith TIN, it shall start transmitting the signal
information about the first two signals on approach of that train. The signal
information shall be in form of packet as described in Annexure-I.
6.32. The signal aspect shall be treated as ‘off’ only when Station/ IBS/ Gate unit has
established that all the following conditions are met:
a. The aspect of the signal is off.
b. If the signal is for main line then all the points in the route of the signal are
in normal position (Only for Station unit).
c. If the signal aspect is for loop line then atleast one of the points taking off
from main line is not normal (only for Station unit).
d. In case of home signal leading to berthing track, the berthing track circuit
corresponding to the signal is clear (only for Station unit).
e. In case of Last Stop Signal (LSS, Advance Starter), both the concerned
station unit have established that block section is free of trains of same TIN
(for Station & IBS unit).
In case of any discrepancy in the conditions mentioned above, the signal
aspect shall be treated as danger & movement authority shall be treated as
zero.
6.33. The point status input as in Clause 6.49shall be used by station unit to identify
whether a particular line is set for main line or not.
6.34. Signal information shall be linked through chain logic wherein previous signal
shall give the id of the next signal and distance to the next signal.
6.35. Loco unit, based on the information received for a signal, shall have the id of
the station/ IBS as well as id of the signal being approached by it. Based on this
information, Loco unit shall receive the signal information packet from Station/
IBS unit for the correct signal.
6.36. The station/ IBS unit shall also transmit the information received from Loco unit’
under its jurisdiction & from adjacent Station/ IBS unit as it is so that all the
Loco unit which are in communication with any of the stations/ IBS of a block
section get the information about each other for collision prevention, stopping
the train/ reducing the speed in emergencies.
6.37. Station unit shall transmit its own SOS message in form of a packet as
described in Annexure-VI.
6.38. Station unit shall transmit timings to Loco unit for train length calculation in form
of packets as described in Annexure-IV.
Communication from Loco unit to Station unit
6.39. Loco unit shall transmit the information in the form of packet as described in
Annexure-IIat every 2 seconds.
6.40. When Loco TCAS is not in communication with any station, it shall transmit the
information by inverting the Tx & Rx frequencies alternatively in case of SOS /
emergency situation.
6.41. The manual SOS & Side Collision messages shall be transmitted by Loco unit
as & when required as described in Annexure-VII and on normal frequency as
well as by inverting the Tx & Rx frequencies every frame.
6.42. While transmitting by inverting the frequencies as per requirement of Clauses
6.40&6.41, the time slots shall be reserved separately so as not to cause
interference with transmission from Stationary TCAS.
6.43. Whenever Loco unit establishes communication with a new Stationary unit for
the first time, it shall do so by Random Access Method within the time slots
reserved for this purpose separately for Up & Dn Trains. Once, Loco unit
receives signalling information packet from Stationary unit, Loco unit shall
continue further transmission in the time slot as specified in ‘Preferred Window’
in the signalling information packet sent by Stationary unit
Signal Directorate RDSO/Lucknow Page 28 of 56