Page 437 - IRSEM_Main Book

D. Reset feautures of MSDAC

The reset arrangement is given at three levels using Track Sections and Supervisory Track
Sections, two of which are automatic reset arrangements and one is manual reset.
(i) L -I : Automatic reset with redundant track section:

Once the train has cleared both the track sections, and any one of the track sections is
in failure state, the track section, which is in clear condition will reset the one in failed
condition. The track section, which is under reset is kept in preparatory mode and the
clear track section information is used to take off the signal.

(ii) L -II : Automatic reset with Supervisory track section:
When a supervisory track section is clear, all the track sections falling completely
within the jurisdiction of that supervisory track section can be assumed to be clear. If
any track section fails and it’s corresponding supervisory track section is clear, it will
automatically reset the failed track section.
In case of automatic resetting with supervisory track section, the reset track sections
will be kept under preparatory mode, and the corresponding signal will continue to be
in ‘ON’ aspect, until a train with low speed enters and exits the track section with
equal count at the boundaries of track section.
As shown in Fig.2, DN-SPT is a supervisory track section which covers all the track
sections of IB in DOWN direction. If any one of the track sections fail, within the entire
IB, DN-SPT resets that track section and keeps in preparatory mode.

(iii) L -III : Manual Reset with Line verification:

In case of failure of Level-1 and Level-2 reset, manual resetting has to be carried out,
which resets all the failed track sections in the section under consideration. One reset
box at train sending station along with its corresponding Line verification(LV) box at
other station is used to manually reset all the track sections between both the
stations of a particular direction of movement. This reset can be done only when
Station Masters of both the stations have ascertained that all the track sections
between the stations are clear of trains in that particular direction. This will reset and
set all the failed track sections in preparatory mode. The clearance of train in each
section with balancing of count will make the track section clear and bring to its
normal mode of working.

E. Power Supply Arrangement

The IB location is provided with a Mini IPS, for which the input supply of 230 V AC is from
UP AT and DN AT. The necessary power supplies for MSDAC are derived from the Mini
IPS. MSDAC works on a voltage range of 19-72 V DC. Hence 24 V DC supply with suitable
current capacity from Mini IPS serves the purpose. In stations, the necessary power
supplies are derived from the Major IPS.

F. Cable requirement

Signaling Cable: In the stations, Home & Advance starter signals are directly fed from the
EI/Relay room with standard signaling cable, with aspect repeating relays at signal
locations. IB Signals at IB location are directly fed using a 12x1.5 Sq.mm signaling cable
from Relay Hut, without any repeater relay at site, as the distance is not more than 200
meters.

Chapter 18: Block Instruments, BPAC& IBS Working Page 385 of 535