A railroad switch is a device used by railroads to allow a train to change tracks. When the train is destined to travel on a set of tracks that are split off of the current set of tracks the train in operating on, the switch-man on the locomotive or another employee in the railroad yard will turn the switch and line the train up on the correct set of tracks. The railroad switch is activated by moving a long arm from side to side and moving the train tracks to the desired position. While most railroad switch activation is accomplished by hand, some are electronic and can be changed by an employee in an elevated office in the railroad yard.
Most of the railroad switch positions in any railroad are locked. This prevents any unwanted rail changes from being carried out. An employee riding in the locomotive has a special key that fits every lock on every rail; this employee is called a switch-man. When plans call for a rail change, the switch-man climbs down from the locomotive as it rolls slowly along and runs ahead to the switch. Once the lock has been removed and the railroad switch has been thrown to the right track, the lock is replaced and the switch-man climbs back aboard the locomotive and it continues on its way.
The railroad switch is equipped with a special reflective marker showing which way it is thrown. This alerts engineers on all trains as to the direction of the tracks. Engineers are taught in their training to not only look at the railroad switch to determine its position, but to also look at the tracks themselves to verify the switch is in fact in the proper position. This prevents a thrill-seeker from dismantling the switch and placing an improper sign on the switch that could lead to a derailment.
Most railroads have reduced speed limits on areas of the track that incorporate switches. This not only reduces the chance for a derailment from running through the switch gates or tracks too fast, but it also gives the engineer a better opportunity to eye the tracks and verify the direction of the switches. The switch is a very durable piece of railroad equipment, however, it will sometimes become bent or otherwise damaged, making it very difficult to change. In this case, a railroad repair or maintenance crew will repair or replace the damaged switch with a new one.