Page 325 - IRSEM_Main Book

(c) The Trackside equipment does not know the train to which it is sending
information. Movement authorities are generated by Trackside equipment
and are transmitted to the train via balises. Balises pick up signal aspects
from the trackside signals via Line side Electronics Unit (LEU) and transmit
them to the vehicle as a movement authority along with track description
data.

(d) The Trackside system shall interface with the signalling system through
LEU without affecting normal working & safety of signalling system. LEU
shall take input regarding signal aspect through potential free contacts of
the Lamp Checking Relays (ECRs).

(e) Because of the spot transmission of data, the train must travel over the
balise to obtain the next movement authority.

(f) The fixing arrangement of the balise on the sleeper shall be such that it
does not require any drilling to the sleeper.

(g) If in level 1, a Trackside signal clears an approaching train cannot receive
this information until it passes the balise group at that signal. The Loco pilot
therefore has to observe the Trackside signal to know when to proceed.
The train has then to be permitted to approach the stopping location below
a maximum permitted release speed. Additional balises (‘Infill balises’) can
be placed in rear of signal to transmit infill information, so that the train will
receive new information before reaching the signal.

(h) Train Detection and Train Integrity supervision are performed by the
Trackside equipment of the underlying signalling system (interlocking, track
circuits etc.) and are outside the scope of level 1`s ATP system.

(i) Level 1 shall have two levels of brake commands.

(i) Service brake command

(ii) Emergency brake command

(j) Release Speed:

(i) A release speed shall be calculated onboard to allow the train to approach
the target (i.e. stop signal at ON) with such speed so as to ensure that the
train stops before reaching the danger point up-to which train movement
is considered safe (i.e., overlap distance beyond the stop signal at ON),
based on data received. The release speed shall be calculated onboard
based on safety distance including signal overlap, deceleration
performance of the train & any other relevant considerations.

(ii) The release speed shall be programmed as a pre-defined value &
transmitted to onboard equipment via the Track side equipment.

(k) If the current train speed exceeds the Release Speed, emergency brake
shall be applied by Level 1.

Chapter 13: ATP, ETCS, IRATP (TCAS) & TMS Page 279 of 535