Railway Track
Overview
A railway track (선로) is a collective term for the railway track facilities laid so that trains can run safely. In a narrow sense, it refers to the track composed of rails, sleepers, and ballast, but in a broad sense, it refers to the entire railway infrastructure, including roadbed, bridges, tunnels, turnouts, and signaling and communication facilities. Railway tracks support the load of trains, guide their direction of travel, and are a core element that determines ride comfort and safety.
Main Content
Components of a Railway Track
Railway tracks are broadly divided into superstructure and substructure. The superstructure is the part that directly contacts trains, such as rails, sleepers, ballast, and turnouts, while the substructure is civil engineering facilities that support the superstructure, such as roadbed, bridges, tunnels, and retaining walls.
- Rail: A steel beam that train wheels directly contact; it distributes loads and guides the direction of travel. Under standard gauge (1,435 mm), 50 kg/m and 60 kg/m rails are mainly used.
- Sleeper: A member that maintains rail spacing and transmits loads to the ballast; types include wooden sleepers, PC sleepers, and steel sleepers.
- Ballast: A layer of compacted gravel (ballast) that supports sleepers and aids drainage.
- Turnout: A device that allows trains to change to another track, essential for entering platforms and car depots.
Track Gauge and Track Classes
Track gauge (軌間) is the distance between the inner faces of the two rails, and includes standard gauge 1,435 mm, broad gauge (e.g., 1,520 mm), and narrow gauge (e.g., 1,067 mm). Korea mostly adopts standard gauge, and high-speed railways (KTX·SRT) also use standard gauge. Track classes are divided from class 1 to class 4 according to design speed, axle load, and traffic density, and the standards for curve radius, gradient, and rail weight differ by class.
Types of Track Structure
Traditional ballasted track (ballast track) is easy to construct and advantageous for absorbing noise and vibration, but requires frequent maintenance. In contrast, slab track (concrete track) fixes rails directly onto a concrete slab, resulting in longer maintenance intervals and suitability for high-speed operation. Most of Korea's KTX Gyeongbu High-Speed Line and some urban railway sections adopt slab track.
Maintenance of Railway Tracks
Because railway tracks wear and deform due to train loads and weather conditions, regular inspection is essential. Track geometry cars (track recorders) measure gauge, cross level, longitudinal level, and alignment, and work such as rail grinding, ballast tamping, and sleeper replacement is performed. Recently, sensors that monitor track conditions in real time and AI-based anomaly detection technology have been introduced.
Recent Trends
As of 2024–2025, railway track technology is evolving toward digitalization, automation, and eco-friendliness. First, smart track management systems that use IoT sensors and optical fiber-based distributed acoustic sensing (DAS) technology to detect rail cracks and abnormal vibrations in real time are spreading. Second, in Korea, as high-speed and high-density track construction increases due to GTX (Seoul Metropolitan Area Express Railway) and KTX expansion projects, the proportion of slab track and ballastless track is growing. Third, in line with carbon neutrality policies, the electrification of track maintenance equipment and the introduction of renewable-energy-based inspection cars are being promoted. Fourth, as autonomous trains and ETCS/ATP-based train control systems are integrated with track signaling facilities, track-train cooperation technology is drawing attention.
Related Topics
- [[철도]]
- [[고속철도]]
- [[궤도]]
- [[분기기]]
- [[KTX]]
- [[도시철도]]