Railway safety depends on more than just trains, tracks, and operators. At the heart of every safe and efficient network lies the signalling system, which ensures trains move at the right time, on the right track, and at the right speed. The invisible backbone of this system is the signalling cable—a specially engineered cable designed to transmit commands and information across the railway network.
signalling cables
In this article, we explore what signalling cables are, how they are built, their key functions, and why they are essential for railway safety.
What Are Signalling Cables?
A signalling cable is a type of railway cable designed to carry low-voltage control signals between trackside equipment, control centers, and trains. Unlike ordinary communication cables, signalling cables must maintain high integrity, immunity to interference, and operational reliability in harsh outdoor environments.
Unique Requirements
Electrical Performance: Must ensure clear, interference-free transmission of control signals.
Mechanical Strength: Resistant to vibration, bending, and crushing from installation near tracks.
Fire Safety: Typically manufactured with Low Smoke Zero Halogen (LSZH) compounds to prevent toxic emissions.
Environmental Resistance: Withstand rain, UV radiation, extreme heat, cold, and even rodents.
Structure of Railway Signalling Cables
Most signalling cables are multi-core cables designed to handle multiple functions simultaneously. Common features include:
Conductor: Usually tinned copper for flexibility and corrosion resistance.
Insulation: XLPE or PVC for electrical protection.
Shielding: Individual or overall screen (aluminium foil or copper braid) for noise immunity.
Sheath: LSZH or PE outer jacket for mechanical and fire resistance.
Core Applications of Signalling Cables
1. Track Circuits
Detects the presence of trains on a section of track.
Ensures signalling systems know whether a track is occupied or clear.
2. Point Machines (Switch Control)
Control turnouts (switches) to guide trains onto the correct track.
Requires precise, interference-free signal transmission.
3. Signal Lights
Control color-light signals that govern train movement.
Failure of these cables can result in serious safety risks.
4. Communication with Control Centers
Links trackside devices with central railway management systems.
Enables centralized monitoring and rapid response in emergencies.
Standards and Compliance
To ensure reliability, railroad signalling cables must comply with strict standards:
EN 50264 / EN 50306 (European railway cables)
BS 6387 (Fire resistance performance)
IEC 60332 / IEC 60754 / IEC 61034 (Flame retardancy, halogen-free, low smoke tests)
These standards guarantee that cables perform under stress while maintaining safety.
Advantages of Signalling Cables in Railways
✔ Safety First: Reliable transmission of control signals prevents accidents.
✔ Durability: Long service life in extreme railway conditions.
✔ Flexibility: Multi-core configurations allow integration of multiple control functions.
✔ Compatibility: Used in both mainline railways and metro systems.
Conclusion
Signalling cables may be hidden underground or alongside the track, but they are indispensable to railway safety. They carry the vital commands that keep trains separated, control their movement, and prevent collisions.
As modern railways move toward digital signalling systems (ETCS, CBTC), the demand for high-performance signalling cables with superior shielding and reliability will only increase.
Looking for more? Check out:
