The EMD F40C is a 6-axle 3,200 horsepower (2.4 MW) diesel-electric locomotive built by General Motors Electro-Motive Division in 1974 for commuter service in Chicago. EMD only built 15 locomotives; the decline of the 6-axle design for passenger service led to the adoption of the 4-axle EMD F40PH as the standard passenger locomotive in the United States. Along with a small fleet of HEP-equipped EMD SD70MAC locomotives operating on the Alaska Railroad, the F40Cs were the last six-axle passenger locomotives in daily service in North America until the delivery of Metra's first SD70MACH in 2022.

The EMD SD70 is a series of diesel-electric locomotives produced by the US company Electro-Motive Diesel. This locomotive family is an extension and improvisation to the EMD SD60 series. Production commenced in late 1992 and since then over 5,700 units have been produced; most of these are the SD70M, SD70MAC, and SD70ACe models. While the majority of the production was ordered for use in North America, various models of the series have been used worldwide. All locomotives of this series are hood units with C-C trucks, except the SD70ACe-P4 and SD70MACH which have a B1-1B wheel configuration, and the SD70ACe-BB, which has a B+B-B+B wheel arrangement.