Reverser handle

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

A reverser handle is a control on a railroad locomotive that sets the train’s direction. It usually has three positions: forward, neutral, and reverse. When set to forward or reverse, the locomotive will move in that direction as soon as you open the throttle. Removing the reverser handle while in neutral locks the throttle and stops the locomotive. The reverser handle is sometimes called a railroad key. On steam locomotives, the lever is often known as a Johnson Bar. The same basic reversing idea has been used on locomotives since early on, with internal-combustion models using similar designs from the early 1900s, with improvements added up to 1996.