A triangular track arrangement with three legs connected by three switches, used to reverse the direction of a locomotive or train without a turntable. Wyes are particularly important at the end of branch lines and in terminal areas where locomotive turning is required. The term comes from the shape's resemblance to the letter Y.
A track assembly consisting of a switch, frog, and closure rails that allows a train to move from one track to another. Turnouts are defined by their angle, expressed as a number (e.g., No. 10 or No. 20), with higher numbers indicating a more gradual diverging angle. They are a critical infrastructure component at every junction, siding, and yard entry.
A track parallel to and connected at both ends to the mainline, used for storing cars, allowing trains to pass each other, or serving customers. Passing sidings are a fundamental capacity tool on single-track mainlines. Customer sidings are used for loading and unloading.
A large rail facility where cars from inbound trains are sorted and grouped by destination to build outbound trains. Cars may be sorted using hump switching, flat switching, or a combination of both. Classification yards are the central nodes of the carload network.