Railway Signalling Cables

Railway Signalling Outdoor Indoor Cables

Cable Schematics Indian Railway Signalling Network Rail Presentation Railways Signalling Cables | Indoor cables | Outdoor cables | Power cables

Railway Signalling Outdoor Indoor Cables

External Data Transmission Cables

1. For axle counter data between the ACE and the EAKs the transmission is over a voice frequency carrier, and hence twisted pair cable is required. Because the transmission distances are restricted to maximum 2 km, it is not necessary to individually shield each pair, and one overall shield is adequate. Power is also fed to the EAK through this cable.

2. These cables are required to be LS0H and UV resistant.
3. The data cable used between the following

– ACE to data CTFs in SER
– Data CTFs in SERs to AJBs

– Data CTF in SER to adjacent SER for ACE to ACE comms.
– AJB to EAK.

Radio Frequency Cables

1. The TBTC system uses Radio Frequency cables mainly for transmission of 9KHz / 36KHz / 56KHz FSK data between the FID and the RLB. Similarly the Axle counter head transmits and receives 29KHz signals from the EAK. The main objective for both cables is to minimise loss and interference.

2. The cables are required to be LS0H and UV resistant.
3. The Radio frequency cables used between followings
– SER FIDs to wayside RLBs
– SER Data CTF and platform docking loop RFBs
– PDIU Electronics rack and Data CTF
FID – Feed In device, RLB – remote Loop Box,
RFB- Remote Feed Box

Inductive Loop Cable

• The Loop cable is unique to the TBTC signalling system. It is laid between the running rails and to the track-bed/ sleepers using variety of clipping methods. It is susceptible to damage from track maintenance and as a result the outer sheath is comparatively thick.

• The cable is required to be LS0H and UV resistant.



Fiber Cables

A key requirement of these cable is non- metallic construction. This is to allow the flexibility to route the cable near to power cables without having to protect against induced voltages.

• The customer requirement is for a non- armoured cable.
• Fibre cables are used between followings

– SCC to SER (via Line splice enclosure)
– SER to Remote terminal
– SCS to VCC

Vital Concentric Signalling Cables

• External Cabling from new SER to trackside equipment will be in standard concentric cable.
• For long cable runs to points electro-pneumatic valves volt drop should be calculated to ensure that it is within acceptable limits.

a) Screened Concentric Cable
b) Non-Screened concentric cable

The screened concentric cable used between the followings with earth free supply.
SER CCTF and the following equipment
– point machine DBs
– Staff protection key switches
– Signals & Trainstops
– Railgap indicator, Direction indicators, Route secure, Track circuit interupter and Tripcock tester.

The Non-screened concentric cable used between the followings with earthed NX supply:
• SER CCTF and the following equipment
– Point machine DBs
– Trainstop

Design Instructions

1. All screens shall be cut back and insulated where the cable is terminated at the external device. Screens shall be electrically insulated form the external device.

2. For cable entering final CCTBs and DBOXs, a maximum of two screens per cable shall be terminated. The remainder, if any, shall be cut back and insulated.

3. For cable leaving the CCTBs and DBOXs (through cables, tail cables, snake), each cable screen shall be terminated separately to facilitate fault finding and maintenance.

4. All screen cables are to be individually terminated for cables entering and leaving an intermediate DBOX.

5. All screens shall be terminated on the “Screen earth bar” at CCTF end to ensure the highest level of electrical and mechanical


Screened Concentric Cable:

Screened Concentric Cable

Vital Signalling Equipment Room Wire:

1. For internal wiring the type of wire used in SER is 0.5 mm sq. or 1.0mm sq.
2. This wire is used for relay rack wiring and SMC PLC wiring.
3. Vital signalling equipment wire is required to be LS0H.

Vital Signalling Equipment Room Wire


Internal Data Transmission Cables

1. For LAN connections to SMC / maintenance workstations in the SER and for the LAN at the SCC a standard FTP 4 / UTP 4 / CAT5 cable is required. Both shielded and non-shielded versions are required.

2. For RS485 communications between cabinet mounted equipment within the SER a twin, individually shielded twisted pair cables is required.

3. A three pair individually shielded twisted pair cable is also required for electrical communication between communication rack, SCS and PDI.

Shielded multi core cable:

1. For non-vital signalling circuits and selected vital circuits it is not possible to route a bulky vital concentric cable, shielded multicore cable type D2 to G7250 is required.

2. These cables are required to be LS0H and UV resistant.
3. The Shielded multi core cable used between the followings:

 SER CCTF to following equipment’s
 Surelock point
 Emergency stop plungers
 Ready to depart indicator
 Staff protection key switches
 Current On line relays
 Points with earth free supply

Unshielded multiple Core Cables:
Docking loops at stations with platform edge doors require a 5 core cable. It is important that the cable is not shielded/ screened/ armored since it is required to act as a multiple turn loop antenna.



External Data Transmission Cables, Radio Frequency Cables, Inductive Loop Cable, Fiber Cables,Vital Concentric Signalling Cables, Vital Concentric Signalling Cables, Screened Concentric Cable,Vital Signalling Equipment Room Wire, Internal Data Transmission Cables, Shielded multi core cable,Unshielded multiple Core Cables

Leave a Reply

Your email address will not be published.