Railway Communication System Equipment

Control Communication Equipment

• Push buttons or soft keys/tabs/buttons should be provided for selective calling of any station by the controller.
• Station masters should lift their control phone and directly talk to the section controller with no dialing or minimum dialing.
• The control phone should have a non-lockable type press-to-talk switch for enabling speech transmission of the station master to minimize background noise while in listening-only mode.

Signalling and Calling Features

• Means should be provided to automatically inform the section controller whenever the bell/buzzer at the station rings in response to the call initiated by him.
• The signalling used for selective calling should not hamper normal telephone conversation on the line.
• Feature of prolonged ringing of any way-station should be provided.

Equipment Requirements

• The equipment should be rugged and capable of intensive use.
• The equipment should work satisfactorily within allowable margins of line characteristics without frequent critical adjustments.
• The system should be capable of progressive expansion without any replacement.
• Earth return circuits should not be retained on AC traction, and all Telecom circuits should work on metallic return or OFC.

CCEO System

• CCEO (Control Communication Equipment for OFC) is an advanced equipment connected to traditional control communication system on OFC.
• The main equipment is kept in OFC hut itself and it works only on standard telecom supply (-48 V DC).

Intercommunication Equipment

• All controllers in a control office should be provided with an intercommunication system covering local requirements with facilities for each controller to call any other controller.

DTMF Calling System

• This system is used for train traffic control equipment with voice frequency signaling using Dual Tone Multi Frequency(DTMF) signals for 4 Wire and 2 Wire operation.
• The control office equipment consists of an operating console with DTMF code generator and voice communication equipment.

Controllers Equipment

• The operating console with code generator has facilities like standard 16 key DTMF Key Pad, station group code buttons, and special push buttons for general call, extending long ring, repeating last transmitted station code, and resetting the system.

Way Station Equipment

• The way station equipment shall consist of DTMF decoder, voice communication equipment, and 2-Wire/4-Wire desk type control telephone.

Control Interruptions Procedure

• As soon as interruption occurs, the Section controller on duty shall localize the faulty section with the help of the way station operating staff.
• Telecom technical staff in the test room/control office and way-station may be called upon to assist in the localisation whenever any technical difficulty arises.

Inspection Records and Reports

• SSE/JE incharge of the control office shall keep a record of all interruptions on the control line as well as failure of way station and control office equipment.

Emergency Control

• Provided from selected points along the track route for establishing communication between train crew, traction and permanent way staff with traction power controller and section controller in non-RE area
• Emergency sockets are provided at an interval of 1 Km (Max.) along the route
• Also provided at FP/SP/SSPs, isolators in yards, LC gates, and both sides of major bridges
• Can be dispensed with specific approval of the Railway Board wherever any other form of emergency communication (MTRC etc.) is commissioned and put into use

Emergency Wireless Control Communication

• Utilizes handsets for Mobile Train Radio Communication (MTRC) in sections
• Utilizes handsets (Official or Private) for Cellular Mobile Communication in sections
• Utilizes Walkie-Talkie sets in sections where VHF communication from train to control office has been provided in lieu of any physical medium or MTRC
• Any other form of emergency wireless communication shall have specific approval of the Railway Board

Train Traffic Control System

• Facilities should be provided to section controllers for selectively calling one or a group of stations or all stations
• Standard 16 key DTMF Key Pad for calling 99 stations with two push button operation
• Station group code buttons A, B, C, D and some additional buttons (4)
• Some buttons are used for Special Functions such as –
  • Push button (marked ‘G’) for general call for calling stations simultaneously
  • Push button LR for extending long ring at way stations
  • Special push button 'RT' - for repeating last transmitted station code
  • 'RS' - to reset the system
  • 'RC' - for row/column frequency check
  • 'DL' - for cancellation of code
• Visual indications for “System O.K”, “Display of station code”, and “power ON” indication
• Communication equipment consists of loudspeaker/microphone with amplifiers and hand micro telephone and controllers headset

Way Station Equipment

• Way station equipment shall consist of DTMF decoder which can be assigned any DTMF station code/group code selectable with DIP switches
• Voice communication equipment and 2-Wire/4-Wire desk type control telephone

CCEO System

• Control Communication Equipment for OFC (CCEO) is an advanced equipment connected to traditional control communication system on OFC
• Main equipment is kept in OFC hut itself and it works only on standard telecom supply (-48 V DC)
• Components of the CCEO system –
  • Control Room Equipment (CRE)
  • Test Room Equipment (TRE)
  • Local Telephone Equipment (LTE)
  • Multi Telephone Way station Equipment (MTWE)
  • Three Way Amplifier (TWA)
  • Remote Patching Equipment (RPE)
• Control Room Equipment (CRE) is provided on the controller’s desk
• Test Room Equipment (TRE) is used for carrying out maintenance and testing functions on way station equipment
• Local Telephone Equipment (LTE) is used to provide 20 local telephones at Head Quarter
• Multi Telephone Way station Equipment (MTWE) is provided at every way station and it is connected to the VF channel from the PD Mux on OFC system by a 4-wire cable
• Three Way Amplifier (TWA) is used when the number of telephones required at a way station is more than four
• Two-Wire Dialing Control Telephone (TDCT) is connected to MTWE with a twisted pair having a loop resistance of less than 1200 Ohm
• Remote Patching Equipment (RPE) is used to provide patching between the two 4-wire VF control circuits available on the OFC system

VoIP based Train Control Communication System

• VoIP Based TCCS is the latest among the various control communication systems being used in Indian Railways
• Leverages open standard IP technology to provide control communication thereby reducing dependence on railway specific equipment/ technology
• Provides the benefit of economy of scale and open market competition using common network infrastructure for voice, video, and data
• Has three major components –
  • Control Communication network (CCN)
  • HQ equipment/servers for control communication
  • Waystation equipment including control phones
• Control Communication Network (CCN) should be kept logically separate from other networks for performance and security
• CCN should be designed using traditional IP components or can be designed as a L3 VPN on Railways MPLS/SDH infrastructure
• OSPF shall be used as the routing protocol
• All Equipment of VoIP based TCCS shall be monitored through an NMS and it is desirable to monitor through mobile dash-boards also
• System should be secure, easy to configure, and maintain

This quiz covers the equipment requirements for railway communication systems, including push buttons and control phones. It also discusses the functionality of these devices, such as selective calling and speech transmission.