The Baldwin RS-4-TC is a diesel-electric switcher locomotive built by the Baldwin-Lima-Hamilton Corporation between July 1953 and January 1955.

The RS-4-TCs were powered by a supercharged twelve-cylinder diesel engine rated at 400 horsepower (298 kW), and rode on a pair of two-axle trucks in a B-B wheel arrangement.

The Caterpillar D397s were chosen for their high speed and small bore and stroke for quick startup and shutdowns.

Even though the 4000s were built for foreign service, very few were actually deployed overseas, the vast majority served in the United States.

Today, the majority of RS-4-TCs have been sold as surplus and are currently serving tourist and shortline railroads with a few still in military service.

The main generator furnishes direct-current power over a wide range of voltage at various speeds up to 1200 rpm.