In case you missed my little joke, GO took old F units, de-motored them and used them for head end power (coach electricity) for use with second hand GP freight diesels.The cabs were left for control purposes. They also had some B units converted the same way, but lacking the cab. Some long GO trains would have 12 cars, with a Geep at one end and a Geep and a B unit at the other. Someone at GO once commented that that was one of their poorer decisions, since one of the railroads (possibly TTR, which controls Union Station) charged them by the axle for access.
Trivia: GO crews called the F40PH "Thunder Wagons" because they had to be run a full speed (notch 8) so the generators would be up to voltage.Imagine the sound of a unit going flat out just sitting in the platform.