A diesel locomotive is a type of railroad locomotive

Locomotive

A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...

 in which the prime mover

Prime mover (locomotive)

In engineering, a prime mover is an engine that converts fuel to useful work. In locomotives, the prime mover is thus the source of power for its propulsion. The term is generally used when discussing any locomotive powered by an internal combustion engine...

 is a diesel engine

Diesel engine

A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel

Rudolf Diesel

Rudolf Christian Karl Diesel was a German inventor and mechanical engineer, famous for the invention of the diesel engine.-Early life:Diesel was born in Paris, France in 1858 the second of three children of Theodor and Elise Diesel. His parents were Bavarian immigrants living in Paris. Theodor...

. Several types of diesel locomotive have been developed, the principal distinction being in the means by which the prime mover's mechanical power is conveyed to the driving wheels (drivers).
Early internal combustion engine

Internal combustion engine

The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

-powered locomotives used gasoline

Gasoline

Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...

 as their fuel.