EMD SDP40

The SDP40 was a 6-axle passenger diesel-electric locomotive built by Electro-Motive Division of General Motors between 1966 and 1970 for passenger service. It shared similarities with its freight counterpart, the SD40, but featured modifications such as steam generators, higher gear ratios, and specific couplers for passenger operation. The locomotive’s design included a modified frame to accommodate a boiler compartment for heating passenger cars.

Externally, the SDP40 had a hood-unit styling, similar to many EMD models of its era, with distinguishing features like a flat rear end, exhaust stacks, and walkways. While it maintained the basic appearance of earlier models, newer versions, such as the SDP40-2, featured updated designs.

The locomotive was primarily operated by the Great Northern Railway (GN) in the United States for passenger service before being converted to freight use after Amtrak’s formation. Some units were sold or repurposed, with several ending up in Mexico following privatization. In Mexico, eight SDP40s were acquired by TFM (later purchased by Kansas City Southern), two of which were rebuilt as SD22ECOs, while the remaining six were scrapped. Another six went to Ferromex, where four were rebuilt as SDP40-2s and remain in service.

One SDP40, originally owned by Great Northern, was preserved and donated to the Minnesota Transportation Museum by BNSF Railway in 2009. It has since been repainted in Great Northern’s orange and green scheme and is operational on the Osceola and St. Croix Valley Railway.