Pennsylvania Railroad No. 5901
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Class: E7a
Built: 1945
Manufacturer: General Motors, Electro-Motive Division
Retired: 1973
The EMD E7A No. 5901 is a diesel-electric locomotive built in 1945 by the Electro-Motive Division of General Motors. It features an A1A-A1A wheel arrangement and is powered by two EMD 12-567A V12 two-stroke diesel engines. These engines drive electric generators that supply power to traction motors mounted on the locomotive’s axles. This configuration, known as diesel-electric propulsion, uses the diesel engines solely to generate electricity, which then powers electric motors to drive the wheels. This system allows for high torque at low speeds, making it effective for pulling heavy passenger trains without requiring external power infrastructure such as overhead wires.
No. 5901 was originally operated by the Pennsylvania Railroad and designated as Class EP-20. It was among the first diesel-electric units adopted by the railroad for mainline passenger service, reflecting a shift from steam to diesel power in the mid-20th century. The E7A design includes characteristic “bulldog nose” styling and is capable of producing 2,000 horsepower with a top speed of approximately 117 mph. It remained in service until its retirement in 1973. The locomotive was purchased by the Pennsylvania Historical and Museum Commission in 1976, making it the only surviving example of the EMD E7 series.