Even though General Motors Diesel of Canada only built EMD locomotives for most of the time, they also designed the GMD1 as their own design. It was a road switcher with the well-known EMD 12-567 prime mover delivering 1,200 hp. There were always four traction motors, but depending on the allowed axle loading on the lines they were supposed to operate on, they could be ordered with a B-B or an A1A-A1A wheel arrangement. The four-axle variant also got a steam generator to be used with passenger trains.

Canadian National ordered 18 four-axle variants and 78 six-axle variants. The only other operator was Northern Alberta Railways with five six-axle GMD1, which brought the total number to 101 and later also became part of CN. With many branch lines being closed or upgraded to heavier rails, many six-axle locomotives were rebuilt to four axles to get a higher adhesive weight for use as switchers. Later some came to new owners in Canada, the US and Cuba, but CN also only retired its last one in 2021.