A control car is a generic term for a non-powered railroad vehicle that can control operation of a train from the end opposite to the position of the locomotive. They can be used with diesel or electric motive power, allowing push-pull operation without the use of an additional locomotive.
Trains operating with a locomotive at one end and a control car at the other do not require the locomotive to run around to the opposite end of the train when reversing direction at a terminus.
Generally, the driver controls the train through a Time-Division Multiplexed (TDM) connection. In addition to the driver's cab, which has all the controls and gauges necessary for remotely operating the locomotive, control cars all have a horn, whistle, bell, or plow (as appropriate), and most importantly, all of the lights that would normally be on a locomotive. Control cars can carry passengers, baggage, mail, or a combination thereof.