Over the course of the history of the locomotive and its components, there have been many propulsion methods. The evolution of the locomotive engine has needed to be adapted in order to accommodate the needs for these differing propulsion methods.

Back in 1753, the first steam engine was received in the American colonies from England. In just a few years, the first steam engine was in use in America. This early steam engine was used to pump water out of a mine.

From that time on, the engine has evolved into the Diesel powered internal combustion engines, then converted into the Diesel-electric engines in use today. The forefather of the Diesel engine was a man named Dr. Rudolf Diesel. His original engine was a compression ignition engine which he patented in 1892. This engine was not efficient though, due to the poor power-to-weight ratio of the first designs.

By the time his patent expired in 1912, the Diesel engine was being used as a means of propulsion for marine vehicles and also for stationary purposes. Due to the size of the engine, they were not initially even considered for use in land based vehicles. Over time, the size was decreased enough to make the Diesel engine a viable option for over land travel.

In 1917, General Electric created a Diesel-electric locomotive using a single level to control the engine and the generator in a coordinated fashion. This caused New York City to ban steam locomotive from the city due to severe pollution problems, prompting the electrification of high traffic rail lines. This was not an economical measure to take in a lesser traffic area though. For this purpose, New York City approached Ingersoll-Rand to construct a prototype switching locomotive. These engines showed that the Diesel-electric engine could give the benefits of an electric locomotive without the rail companies needing to finance the electrification of the rails.

Diesel-electric propulsion started to become mainstream after 1939. Burlington Northern and Union Pacific helped bring these engines into widespread use when they used the Diesel engines to haul passengers. This prompted the change from the steam engine over to the Diesel locomotives.