The Motive Power Industries MPXpress series of North American passenger train locomotives is based on a common platform, but almost each component is able to be customized to a specific customer's needs. It currently meets all FRA, APTA and EPA safety and emissions regulations.

Although it is unmistakably different than anything else on the outside, the MPXpress is based on MPI's experience producing both new and remanufactured commuter locomotives to many commuter agencies across North America. Even though it is marketed as a new locomotive, it is even available with a host of remanufactured components to help lower costs for any potential customer. 

There have been three major variations built of the MPXpress: The MP36PH-3S, the MP36PH-3C and the MP40PH-3C.

The MP36PH-3S is the first version built, and has only been built for Chicago’s Metra. It is powered by a 3600 horsepower 16V-645F3B motor. Rather than using a separate diesel engine to provide Head End Power for the passenger cars, it uses a series of static invertors instead, which also reduces the amount of power available to move the train.

The MP36PH-3C has been the most popular version of the locomotive built. It is powered by the same 3600 horsepower motor as the MP36PH-3S, but uses a small separate diesel engine to provide Head End Power.

The MP40PH-3C is the newest version of the product line. It is outwardly identical to the MP36PH-3C, but is instead powered by a 4000 horsepower 16V-710GB motor provided by Electro Motive Diesels Inc. EMDI also provided all of the electrical systems and computer equipment necessary to run the locomotives. Only GO Transit in Toronto has purchased these locomotives.