Switch

A switch is a track device that guides equipment from one track to another, allowing a train or car to move from a given track onto a diverging route. It is the basic mechanism that makes a network of tracks possible, letting trains be routed, sorted, and stored rather than confined to a single line.

How It Works

A switch contains a pair of movable, tapered rails called points (or switch points). Depending on which way the points are set, the wheels of an approaching car are guided either straight ahead or onto the diverging track. Where the two routes cross, a casting called the frog carries the wheels through the crossing of the rails, and guard rails on the opposite side keep the wheels properly aligned so they follow the intended path.

Hand and Power Switches

Switches may be thrown by hand or by power. A hand-throw switch is operated by a crew member who moves a lever or switch stand to line the points; a power switch is thrown remotely by a control system, as in interlockings and in hump yards where computer-controlled switches route cars automatically during classification yard sorting. However it is operated, a switch left lined the wrong way can send equipment onto an unintended track, so proper alignment is a fundamental part of safe operations.