Production/ Batch tests 

The following test will be performed on every manufactured batch of cable.

Spark test:

• The test procedure shall be as defined in LU specification E4156. The test shall be performed on the conductor and screen insulation during manufacturer.

• Voltage withstand and insulation resistance test on complete cable(tested dry). The conditioning, test procedure and results supported shall be as defined in LU specification E4156. The test shall be performed on the entire manufactured length of cable. No insulation breakdown shall occur. The insulation resistance shall be atleast 350 mega ohms per kilometer.

Production/ Batch tests:

• Voltage and insulation resistance test on cable components (tested wet). The conditioning, test procedure and results supported shall be as defined in LU specification E4156. No insulation breakdown shall occur. The insulation resistance shall be atleast 350 mega ohms per kilometer.

Conductor resistance test:

• The test procedure shall be defined in LU specification E4156. The test shall be performed on the entire manufactured length of cable. The conductor resistance shall be in accordance with the manufacturer’s design.

Life expectancy:

• The cables once installed shall remain in constant service for an expected 40 years as per LUL specification E4156.

Cables Availability:

Vital concentric signalling cables
• 1 pair
• 3 pair and
• 7 pair

Shielded multicore cables 1.0 mm²
• 2 core
• 4 core
• 6 core
• 7 core
• 12 core
• 16 core and
• 27 core

Cables Availability:

Shielded Multi core cables 1.85 mm²
• 2 core
• 4 core
• 6 core
• 8 core
• 10 core
• 16 core
• 19 core
• 27 core and
• 37 core

Cables Availability

Flexible Screened Multi core cable
• 2 core
• 4 core
• 6 core
• 7 core
• 10 core and
• 12 core
Track connection cable
• 1 core
Track crossing cable
• 5 core
• 10 core

Cable Routes:

• Vital signalling cables shall be kept separate from power cables and, where possible, from control systems and communications cables, e.g. by running in separate shelves of a cable run. (Cat 2)

• The route shall have the capacity to hold all the required cables, together with a 20% spare capacity to cover future needs.(Cat 2)

Design Consideration:

• All track side signalling equipment shall be connected locally to the main track side signalling cables via track side disconnection boxes to facilitate ease of installation, maintenance testing and fault finding.

• All equipment requiring greater than a two wire (plus earth) connection shall be connected via a keyed plug and socket (or equivalent) system which is constructed to a grade of appropriate integrity.

Other Consideration:

a) All cable types shall be identifiable by examination of the sheaths.
b) Cable routes shall be designed to suit the mechanical characteristics of the cable and the installation techniques to be employed. When utilising exiting cable routes, the mechanical characteristics and installation techniques shall be selected accordingly.

c) Where cable routes cross the track they shall be in either overhead runs or in purpose designed cable ducts which fully protect them and do not require the cables to be disturbed during track renewal.

d) With the exception of main power supply cables, all cables entering and leaving signalling equipment rooms, signal apparatus boxes and wayside kiosks shall be terminated on separate cable racks in order of their core numbers on a combined terminal or disconnection, or terminal or fuse links. Each wire shall be capable of being individually disconnected and isolated without removing the wire itself. These links shall be easily accessible for test purposes. Each link or terminal shall be identified and labelled. Power supply cables shall be terminated by a means appropriate to their size and current capacity.

Internal Wiring:

1. All wires shall be terminated.
2. Every end of a wire shall be labelled at the ends of its termination points. The label shall be of a form which cannot be removed without disconnecting the wire.

3. Wire racking shall be earthed and provision made, where practicable, for the isolation of individual racks for fault finding.
4. No joints or splices of any type shall be permitted in wires between terminations.
5. Redundant wiring shall be removed. In the event that a concession is granted to allow the non removal of a wire, then that wire shall be so identified with a label.

Where it is not practicable to physically remove disconnected wiring, the ends shall be cut back ,capped and secured

Circuit requirement

1. Circuits leaving or entering the SER shall be protected by links or isolators. These links or isolators shall be of a type capable of being secured in the isolated condition.

2. Where there is significant risk that the circuits may come into contact with 600V traction rails (e.g. track circuits rail connections) then the links or isolators shall be replaced by fuses or suitable protective devices. Links, isolators, fuses or MCB’s used at the entry point of SER’s on new installations shall provide touch protection against electric shock.

3. They shall also incorporate touch protected connection points on both sides of the isolation to permit a remote switch to be wired across the isolator for simulation purposes during testing, and for the application of test instruments during fault finding. These connection points shall permit the rapid disconnection of the simulation facilities without disturbance to the permanent wiring. The exact form of connection shall be agreed with the Trains System Engineer.

4. A maximum of two wires shall be connected to any one terminal except on diagrams where terminals are provided for multiple connections.
5. A minimum of 10% spare terminals shall be provided on each terminal block on the rack. Terminals used to terminate spare multi core wires shall not be considered as spare terminals.

6. There shall be only one feed per circuit.
7. Where plug connections are used, the wiring shall be arranged such that no voltage is present on exposed pins when disconnected. The plug connectors used shall be mechanically keyed to prevent improper insertion and identify equipment of compatible types.

8. Cable cores, whether main cables, tail, or multi cores shall be terminated. It is not permitted to cut back spare cores in SER’s containing safety wiring.

Production Validation:

1. No cables or wire shall be supplied unless a formal ‘Authorised to supply product’ letter covering the specific cable or wire concerned has been issued by LUL’s Standards Engineer or the materials engineer of an Infraco.

2. Grandfather rights shall not be an acceptable alternative to an ‘Authority to supply product letter’ issued as a result of successful product validation to current standards.

3. For cables or wires that are not already covered by an ‘Authorised to supply product’ letter reference should be made to E4156 for the testing and documentation that must be submitted by the supplier to Thales.
4. Copper conductor resistances should be in compliance with BS6360. The referenced typical PICO values are a guidance for installers only.

TYPE TESTS:

1. The details of the type tests required are specified in E4156 (Appendix B & C).

2. The requirements of 2-01001-002 for fire performance supersede the smoke emission, toxicity and flammability requirements of E4156 or those found in any of the particular cable specifications referenced.

3. Suppliers attention is drawn to the relevant clauses in E4156 concerning the restrictions on acceptable testing facilities.

Fire Performance Requirements

1. The fire performance requirements for cables on London Underground infrastructure are extremely stringent, refer to LUL Standard 2-01001-002 A1, Fire Safety performance of materials.

2. The Supplier will be required to conduct type tests, in accordance with E4156 and 2-01001-002, Fire Performance, in particular covering the three main areas of Flammability, Smoke Emission and Toxicity.

3. The Jubilee and Northern Lies are predominantly tube section and therefore LS0H sheaths and non-PVC insulation will be a standard requirement of most cables.

Production/ Batch tests, Spark test, Conductor resistance test,Life expectancy,Cables Availability, Flexible Screened Multi core cable, Cable Routes,Design Consideration,Internal Wiring, Circuit requirement,Fire Performance Requirements

Track Connection Cable

1. A single core flexible cable used to connect to items of track-mounted equipment.

2. The cable will be installed in the most difficult locations and will need to be highly rugedised to withstand both the high levels of vibration associated with track mounted equipment as well as being crushed into the ballast during track patrolling operation.

Track circuit Interrupter

Track Crossing Cable:

Operational Requirements:
1. The cables shall be suitable for passing under railway tracks, being laid directly on ballast, and shall be resistant to abrasion, crushing, oil, water, fire and atmospheric conditions.

2. The cable will be installed in the most difficult locations and will need to be highly rugedised to withstand both the high levels of vibration associated with track mounted equipment’s as well as being crushed into the ballast during track patrolling operation.

3. Multiple flexible and individually screened cores.
4. This cable runs from wayside disconnections box on the one side of the track to wayside disconnection box or signalling equipment on the other side of the track.

Under Track Crossing (UTX)

Over Track Crossing (OTX)

Track Crossing via Plastic PIPE/ Track Hose

Cables in Tunnel

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.
Types:

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
Integrity.

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.

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

What Are Cables? 

A cable is a unit that contains more than one insulated conductor bunched into a compact form by providing mechanical protection and electrical insulation. PVC insulated, PVC sheathed and armoured signalling cables are used for carrying signalling circuits. Conductors are of copper and of approved size. Cables are classified as „INDOOR‟ cables and „OUTDOOR‟ cables.

What is the use of Indoor cables?

Used for internal wiring of signalling circuits with copper conductor, PVC insulated without armour. Indoor cables are normally in size 60 core, 40 core, 24 core, 20 core with conductor size 0.6 mm dia. or 60 core, 40 core, 24 core & 16 core of 1.0 mm conductor dia. size.

Outdoor cable

These are classified as Main cable, Tail cable, Power cable and Quad cable as per circuit connection requirement. Main and Tail cables are available in 4 core, 6 core, 8 core, 12 core, 20 core, 24 core, and 30 core, with conductor size 1.5 sq. mm area. 1.5 sq mm (Copper conductor) 2 core size cables are used for track circuits (Feed end & Relay end) Numbering is generally started from outermost layer i.e., Starting from Blue and ends with Yellow.

Power cable

Used as BUS BAR for power supply from relay room to location boxes. Sizes are 10 sq mm Aluminum single strand 2 core cable. 25 sq mm Aluminum single strand / multi-strand 2 core.

Quad cable

Used for Axle counter circuits, Block line circuits. There are of 6 or 4 quad cable (1 quad = 4 conductors arranged in 2 pairs)

Testing of signalling cables

Periodicity of the Main cable Once in a year, Tail cable Once in six months, Life of signaling cable 30 years, 500 volts DC Megger to be used for testing of the cable. The insulation resistance should not be less than 5 Megohms / Km in dry weather. (For 500 Mts. 10 Meg ohms, 250 Mts. 20 Meg ohms)

Electrical Key Transmitter

The electrical key transmitter is used for the purpose of controlling a signal apparatus such as points, LC gates & signals, etc by SM by retaining the key of the controlled apparatus (which is normally locked) and issuing the same key for releasing the apparatus when required.

Under this system, the working of fixed equipment is locked by means of a mechanical key which is electrically locked in the EKT. For extracting the key from the EKT, a pair of EKTS is required to be connected in series, one at the function end and the other at the controlling end and requires physical co-operation from both end operators.

The EKT keys are so designed that they enter only the instrument meant for the specific key and can not enter any other instrument of its kind. The EKTs keys are provided with the provision of sealing.

Railways Signalling Cables Indoor cables Outdoor cables Power cables

Keys out: All contacts open
Key in & pressed to right side : Contacts 5 & 4; 3 & 1 make
Key in : Contacts 5 & 4; 3& 2 make

Electrical parameters:
Resistance of coil – 12.5 ohms to 15 ohms
Rated voltage – 12 V DC
Working current 150 mA to 200 Ma
Minimum Voltage 6V DC

Railways Signalling Cables Indoor cables Outdoor cables Power cables Visit Here:- http://rdso.indianrailways.gov.in 

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