switchyard

A switchyard is a section of railway infrastructure where track switches (or points) are arranged in a network to redirect rolling stock onto different lines. Unlike main-line track, a switchyard contains no revenue-generating traffic; instead, it serves as a sorting facility where incoming trains are broken apart, individual cars are routed to different sidings, and outgoing consists are assembled according to their destinations. Switchyards handle the physical work of marshalling, a function essential to rail freight operations.

The core equipment is the switch mechanism itself: a movable rail section that can direct a wheelset onto either of two diverging tracks. Switches are powered hydraulically or pneumatically on busy yards, and hand-operated on smaller facilities. A switch stand or lever frame controls the points, and interlocking systems prevent conflicting switch positions. Multiple switches arranged in ladder or ladder-diamond patterns allow cars to be routed laterally across parallel sidings without blocking the main line.

Yard layout and operations

A typical freight switchyard is divided into receiving sidings where inbound trains arrive, a hump or gravity section where cars roll to their assigned tracks, and departure sidings where outbound consists are built. Larger yards employ a hump: an elevated section from which individual cars are pushed or released to roll downhill under gravity into classification tracks, where retarders (friction devices) control speed. Cars are sorted by destination, commodity, or next-stop requirement. Smaller yards use flat switching, where a locomotive or switch engine physically moves cars between sidings.

Switchyards are heavy users of labour and equipment. Crews include switchmen, hump operators, and car riders who couple and uncouple cars. A modern interchange yard can handle 2000 to 5000 cars per day depending on size and automation level. Automation has grown steadily: electronic routing systems, RFID car tracking, and automated switch control reduce manual work, but even highly mechanised yards require human spotters and mechanics to manage exceptions and maintain the complex network.

The term switchyard is specific to railways; trucking terminals use the word yard alone. In American practice, large yards serving multiple railroads or acting as consolidation points are called classification yards. The switchyard sits between the main line and the local siding network, making it the critical node where freight is sorted, delayed, and redistributed. Poor yard productivity or bottlenecks can ripple back onto the main line, making switchyard design and staffing decisions important to overall rail efficiency.