Indian Railways Other Networks

From an operational point of view, the Indian Railways have been divided into

various hierarchies viz. the railway board, zone and division. The division is

the primary unit, which deals with day-to-day train operations. Each division

has many section controls, having jurisdiction over 150 to 200 rkm. The section

controller requires communication with each station, called section control

communication for real-time controlling and monitoring of train operations. A

telecom network is also required for the flow of the administrative instructions

between the various hierarchies of the railways.

The railways’ telecom requirements can be categorized as follows.

• Control communication: For controlling the movement of the trains.
  
  The control communication is between the section controller and each station
  
  in his jurisdiction.

• Administrative communication: For monitoring the
  
  operations and flow of administrative instructions. The major activity
  
  centers and the headquarter offices like the railway board, zonal railways
  
  headquarter, production units, divisions, etc., are connected with each
  
  other. This is provided with the help of the telephone exchanges–connecting
  
  them through a microwave network.

• Emergency communication: For the communication
  
  between the train crew and the section controller for reporting emergencies,
  
  etc.

The railways requirement for control and emergency

communication is both unique and exclusive. Presently, the control communication

is working either on an overhead alignment or underground copper cables, which

also carry the vital block circuits. The block circuits are vital circuits, as

these circuits ensure that only one train enters the block section at a time.

Besides the emergency communication through which the crew reports emergencies

to the section controllers, are also the vital circuits. Emergencies like

disruption of traffic, accidents, etc., are reported through the administrative

circuits to the divisional and zonal headquarters, railway board and others for

taking corrective action.

The Radio Network

During the early stages, the DoT used to meet the railways

requirement of telecommunications. However, the DoT was unable to connect major

activity centres, which were important from the railways viewpoint, but

otherwise commercially unviable. Hence, the railways had to start establishing

their own telecom network.

The railways have been installing the microwave network for

long distance communication, primarily used for administrative communication. In

addition, the availability of the microwave link has also made it possible to

use the links for providing radio patching in the control circuits.

For their microwave network, the railways have been allotted

a 300 MHz slot in 7 GHz band. The old analog microwave network, having served

its useful life, is being replaced by a state-of-the-art digital microwave

system.

The Indian Railways had been facing acute problems in control

communication, especially in the eastern sectors, due to the frequent theft of

underground copper cable, which was used for the train control communication.

The Howrah-Mughalsarai section on the Eastern railway is an important section

linking both the eastern and the northern regions. The density of the trains in

the section is very high and an interruption in the communication circuits

adversely affects the railway operations. Hence, the railways have decided to

use the 18 GHz frequency band for providing control communication on which the

vital block circuits are also working. The 1,000 km long link in this section is

probably the longest 18 GHz link working in tandem.

Passenger Safety

The utility of providing communication to the crew of the

train is undisputed, as far as the safety and efficiency of the train operation

is concerned. The railways are still using a primitive mode of communication for

this purpose. The crew is provided with a portable emergency control phone,

which can be hooked on to overhead alignment in a non-electrified territory or

connected to sockets in an electrified territory to talk to the controllers.

However, in this arrangement, the controller or stationmaster is unable to

contact the crew when required. Besides, the crewmembers are also not able to

speak to each other. To overcome these difficulties, the following steps have

been taken:

• Provision of walkie-talkie sets to the drivers and
  
  guards: 5 watt walkie-talkie sets are being provided to drivers and guards
  
  of trains for communication in a static mode, during emergencies like train
  
  parting, rolling stock, pulling of the alarm chain, etc. The walkie-talkie
  
  sets have already been provided to the drivers and guards of all
  
  mail/express/passenger trains.

• The mobile train radio communication: It has already been
  
  decided to provide the Mobile Train Radio Communication (MTRC) system on
  
  important routes where the mail/express trains are running and the sectional
  
  speed is very high. The MTRC system enables the establishment of
  
  communication in a duplex mode–where both the parties can talk
  
  simultaneously–between the driver and the guard and between the
  
  driver/guard and the nearest station/control office.