Page 321 - IRSEM_Main Book

Chapter 13: ATP, ETCS, IRATP (TCAS) & TMS

Section 1: General Requirements

13.1.1 Definitions: Please refer to Glossary for definitions of Technical terms used in
this chapter.

13.1.2 There are two types of Automatic Train Protection (ATP) Systems.

(a) European Train Control System (ETCS) having four levels- Level 0 to Level 3.

(b) Train Collision Avoidance System (TCAS) - Indian Railway`s ATP System.

13.1.3 ATP requirements

(a) ATP systems shall confirm to latest specification and shall be of approved
type.

(b) ATP systems shall be suitable for working on Electrified and Non-Electrified
sections.

(c) Functions in ATP systems shall comply with the Safety Integrity Level as
stipulated.

ATP systems shall have two sub-systems viz. Trackside and On-board.

13.1.4 Trackside:

(a) Movement Authorities (MA) shall be generated by trackside equipment
based on input received from signal interlocking.

(b) The track description data such as Permanent Speed Restrictions,
Gradients, Level Crossing Gates, etc. are to be pre-fed in the track side
equipment.

(c) The trackside equipment shall Communicate MA to on board equipment
along with track description data.

13.1.5 On-board:

(a) The On-board equipment of the ATP shall be correctly and effectively
interfaced to existing Air/Vacuum/Dual/Electro-pneumatic brake system of
Diesel and Electric Locomotives as well as other self-propelled vehicles
treated as train.

(b) The On-board Vital Computer (OBC) shall calculate the maximum
permitted speed for the track section ahead based on a dynamic speed
profile taking into account the train running/braking characteristics which
are known on-board and the MA (Movement Authority) and track
description data received from trackside.

(c) It shall continuously supervise the train speed and apply brakes if the train
speed exceeds the most restrictive speed by a pre-defined speed margin.

Chapter 13: ATP, ETCS, IRATP (TCAS) & TMS Page 275 of 535