EMD GP40-2

The GP40-2 was rated at 3,000 horsepower and entered production in 1972. It was a four-axle diesel-electric locomotive built by General Motors’ Electro-Motive Division. [EMD specification](https://www.chartertoconductor.com/wp-content/uploads/2021/07/EMD-Locomotive-Specification-Book-GP40-2-SPEC8091-03JAN72.pdf)

GP means General Purpose, while the 40 identifies the model family and the -2 marks EMD’s Dash 2 electrical and reliability improvements. The specification sheet describes it as a 3,000-horsepower general-purpose diesel-electric locomotive from January 1972. [EMD specification](https://www.chartertoconductor.com/wp-content/uploads/2021/07/EMD-Locomotive-Specification-Book-GP40-2-SPEC8091-03JAN72.pdf)

It was primarily a freight locomotive used for road service, switching, and general-purpose duties across North American railroads. Its four-axle layout made it more flexible on many routes than a larger six-axle locomotive. [Wikipedia](https://en.wikipedia.org/wiki/EMD_GP40-2)

Both use the EMD 645 engine family and produce about 3,000 horsepower, but the GP40-2 has four axles while the SD40-2 has six. The SD40-2 generally provides more adhesion for heavy trains, while the GP40-2 is lighter and more route-flexible. [Wikipedia](https://en.wikipedia.org/wiki/EMD_GP40-2)