GSRM maintains two operating diesel locomotives:
* NSP4 - a 1940, 600 horsepower Electro-Motive Corporation model SW-1. NSP4 was originally built as Chicago, Burlington & Quincy number 9146. It was last used by Northern States Power at its St Paul High Bridge plant and donated to GSRM by NSP in operating condition. It feature's NSP's trademark mascot "Reddy Kilowatt" on its cab.
* FW1 - a 1954, 1000 horsepower Alco model S-4. FW1 was originally built for the Ford motor company as part of its fleet of locomotives assigned to switching Ford's River Rouge assembly plant. It's Ford road number hasn't been determined yet. FW1 was last used by the University of Minnesota to unload coal hoppers at its Minneapolis Campus steam plant. UofM staff gave it the number "FW1". The locomotive was purchased from the UofM in 2020 for $1.00 plus sales tax.
Choice of locomotive depends on which one is selected by GSRM mechanical staff as the locomotive of the day.