The 15 model F40C's, including #611, were purchased in 1974 for use on the Milwaukee District. At the time, it was believed that six axles would be the norm for passenger locomotives. Amtrak meanwhile was acquiring SDP40F's, which were physically similar but had steam generators instead. The F40C was GM-EMD's first use of a constant speed engine, which also drives an auxiliary head end power generator. The F40C's remain in Metra service until their retirement in 2004, while problems with derailments resulted in Amtrak trading in its SDP40F's for four axle F40PH's.
The F40PH eventually became the standard locomotive for Metra, and for North American passenger railroads in general. #140 is an example. As with the F40C, a constant speed engine also drives an auxiliary head end power generator.
Metra's last locomotive order in a long time was for the F40PHM-2, with a modified cab design. These locomotives are used on the Burlington Northern Santa Fe line, and on the Rock Island District, including #212.
In 2003 and 2004, Metra finally received new MP36PH-3S locomotives from Motive Power Industries of Boise Idaho, equipped with GM-EMD engines.
Metra also acquired a few second hand switchers for shop and yard use. SW1500 #4 is seen at La Salle Street Station.