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.
Cab cars are control cars similar to regular passenger car, but with a full driver's compartment built into one or both ends. They can be very similar to regular railcars, to the point of including a gangway between cars so that they could be used in the middle of a passenger train like a regular car if necessary. They appeared for the first time in the United States and France in the 1960s.
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. Control cars can carry passengers, baggage, mail or a combination thereof, and may contain an engine-generator set to provide head end power.