Page 402 - IRSEM_Main Book

(j) The power to evaluator is fed from a power supply like DC-DC converter
of approved type with adequate battery backup. Each evaluator shall be
provided with a separate DC-DC converter for better availability. The input
power supply shall have a maximum ripple of 50 mV peak to peak/10 mV
rms.

(k) All lead connections to and from battery and DC-DC converter shall have
adequate current capacity to ensure that the voltage drop does not exceed
0.2 V. These connections at terminals shall be secured properly and should
preferably be made through lugs to give firm contact.

(l) Connections between battery, battery charger and DC-DC converter shall
not be bunched with any other wires. These wires shall preferably be laid
at least 150 mm from any other bunch of wires. Positive and negative
wires shall be twin twisted to avoid interference pick up especially when
the lead wires are long.

(m) Where ever Integrated power supplies are provided, power for axle counter
shall be taken from nominated DC-DC module.

(n) Redundancy in train detection devices may be provided for all train
detection device in Block section and at vulnerable Track sections within
station section. Redundant system shall be independently powered through
independent power source and separate cable.

17.7.3 Communication Media

(a) The quad cable or PIJF Telecom Cable used with axle counters shall be of
approved type. The Transmission loss, cross talk measurements shall be
within limits specified for the axle counter to be installed. Optical Fibre
Cable (OFC) may also be used for communication with suitable interfaces.

(b) All precautions prescribed for laying and installation of communication
cables shall be strictly followed.

17.7.4 Axle Counter Resetting - Block Section/Intermediate Block Signalling/
Automatic Signalling:

(a) Preparatory reset arrangement shall be provided, so that whenever the
axle counter shows fault condition; the same can be reset by the on duty
Assistant Station Master/Station Master (ASM/SM), after ensuring that the
monitored portion is clear of vehicles.

The following precautions shall be followed for resetting.

(i) Once the Axle Counter has failed and the concerned signal cannot be
taken off, the on duty Assistant Station Master (ASM) of Train
dispatching station shall positively verify the clearance of the block
section with the on duty Assistant Station Master (ASM) of Train
receiving station by exchange of private numbers and record the same
in Train Signal Register (TSR) by both the stations. After ensuring that
the block section is clear of vehicles, Axle Counter`s reset operation
shall be initiated by cooperative effort between the ASM`s of the
dispatching and the receiving stations.

Chapter 17: Train Detection Track Circuits & Axle Counters Page 350 of 535