How Signalling
System in the Indian Railway Works
At first the most important thing to say that "A Driver of a train shall not start his
train until he is authorised to do so". To give authority to the
driver to start, signal posts have been erected at various places to indicate
him whether to start or not. The driver shall not pass a signal unless he sees
it has been TAKEN OFF i.e. Signal turned to either GREEN, or TWO YELLOW or ONE
YELLOW. If the Signal is at ON position, i.e. RED, he must not pass it unless
he is authorised to pass on a Written Authority issued by the Station Master.
(This is done in case of Signal Failures).
There are certain circumstances in which although signal is
RED, yet written authority is not required. For example GATE SIGNAL,
INTERMEDIATE BLOCK STOP SIGNAL, AUTOMATIC SIGNAL.
To ensure a train shall proceed safely from one station to
other there are various SYSTEMS of WORKING adopted in Indian Railways. The
system adopted depends upon the density of traffic, i.e. more the number of
trains the more costly the system adopted. Among this system, any one is
followed for running of trains between two station. These systems are:
1. ABSOLUTE
BLOCK SYSTEM
2. AUTOMATIC
BLOCK STSTEM
3. FOLLOWING
TRAIN STSTEM
4. PILOT
GUARD SYSTEM
5. TRAIN
STAFF TICKETING SYSTEM
6. ONE
TRAIN ONLY SYSTEM
ABSOLUTE BLOCK
SYSTEM
|
Block Sections
(in RED)
|
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In Absolute System of Working a long section is divided into
small blocks called BLOCK SECTIONS and
the stations dividing the block sections are called BLOCK STATIONS. For a train to leave from a block station and
proceed towards next block station, LINE
CLEAR must be obtained from the next
block station. If the next station is able to receive the train then he gives
the line clear to the rear station. This line clear is done with some device to
enhance the safety. Generally ELECTRICAL BLOCK INSTRUMENTs are installed for
such purpose. The system through block instrument is such that the signal from
rear station cannot be given, unless line clear has been obtained from advance
station through block instrument.
This system is called Absolute Block system, because in this
system, at any point of time, only one train can be in a block section running
from a block station to another. It ensures perfect safety against two trains
in one section.
 |
AUTOMATIC BLOCK
SYSTEM
Sequence of Change of Signals with respect to running
train in Automatic Block System
This system is improvement over the Absolute Block System.
In this a block section between two block station is further sub-divided into
different block signalling section. Which means where one train can run between
two block station in Absolute Block System, there more number of train can run
in between two block stations.
ASPECTS OF AUTOMATIC SIGNALS
Sequence of Change of Signals with respect to running
train in Automatic Block System
In Automatic Block System, each signals convey the aspect of
next Signal(s) to the driver. For example, if a signal is ONE-YELLOW, it tells
the driver that the next signal is RED. If it is DOUBLE-YELLOW, then next
signal is DOUBLE-YELLOW or ONE-YELLOW, and if it is GREEN, then next signal is
either GREEN or DOUBLE-YELLOW.
Each signals telling
the driver the aspects of next (few) signals helps the driver to run the
train at more speed and helps him to control the speed when required.
Also Read: systemsof working in indian railways
