With the expansion of railway transportation networks, significant progress has been achieved in this field, driven by technological advancements. One of the most critical outcomes of these developments has been the increased emphasis on selecting the right materials. The components that ensure continuity in energy transmission and communication systems are railway cables.

Railway investments, which began during the Ottoman Empire, accelerated in the early years of the Republic of Turkey. The ambitious project to weave the nation with iron networks reached a level of pride. However, after the 1950s, railway transportation was pushed into the background, replaced by highways and motor vehicles. For decades, railways were neglected, but with the introduction of the “Accelerated Train” and later the “High-Speed Train,” modernization efforts gained momentum, particularly with the renewal programs accelerated up to 2023.

As railway networks expanded, the industry witnessed remarkable growth in line with technological progress. The most important achievement has been the heightened sensitivity toward proper material selection. Railway cables—responsible for ensuring continuity in energy, signaling, control, and communication—have become indispensable components of modern railway systems.

Despite the undeniable importance of railways in transportation and logistics, the sector lagged in applications and technology for many years, with insufficient investments. More expensive and less secure road transport was prioritized instead. Today, however, the importance of railways is increasing, investments are being made, and advanced technological products developed specifically for railway applications are taking their place in the sector.

By employing high-technology materials, systematic operations have been established, leading to significant progress in this field. From this perspective, the selection of cables—particularly those used in energy transmission and signaling—is a critical criterion for the reliability and efficiency of railway infrastructure.

Figure 1: In parallel with technological advancements, cable selection in railway systems has gained significant importance. Depending on varying conditions and areas of application, cable structures and properties may differ. By taking these criteria into account, the railway sector can deliver higher quality and uninterrupted services.

Cable Types Used in Railways

In railway systems, three primary types of cables are utilized. These cables perform the essential operational functions of the railway infrastructure and must operate without interruption. Produced in accordance with the specifications of the Turkish State Railways (TCDD), these cables undergo rigorous testing to ensure compliance with field requirements and operational standards.

The main cable types are:

• Signaling Cables – Ensure safe train operations by transmitting control and signaling data across the railway network.
• Communication Cables – Provide reliable telecommunication and data transfer between trains, stations, and control centers.
• Power Cables – Deliver electrical energy required for traction, auxiliary systems, and overall railway infrastructure.

Figure 2: Cable types used in railway systems can be classified according to functionality and structure.

• By Functionality:
  • Tinned conductor signaling cables
  • Armored and shielded signaling cables
  • Halogen-free flame-retardant cables
  • Data and communication cables
  • Control cables
  • Low-voltage cables
• By Structure:
  • Insulation type
  • Core colors
  • Arrangement of conductors
  • Sheath design
  • Armoring
  • Cable diameters

Signaling Cables These are employed in electrification systems operating at 25 kV, 50 Hz single-phase with rail return current, ensuring reliable connections between signaling equipment along the railway route.

Communication Cables Used in voice frequency circuits (information communication, dispatcher telephones, maintenance telephones, and other railway telephony systems), these cables provide long-distance connectivity and serve as essential components in railway control and monitoring systems.

Power Cables Installed along railway lines, power cables are responsible for transmitting the energy required for lighting, switch heating, and ventilation systems, thereby ensuring the continuous operation of railway infrastructure.