The prototype GMD-1 locomotives were a huge success. When CN started closing down the branchlines for which the GMD-1 locomotives had been designed, it was decided to rebuild the reliable locomotives for general service. The rebuild included new 2000-gallon fuel tanks, upgraded steps and sanding equipment, and 4-axle Flexicoil trucks salvaged from retired lightweight GP9 locomotives.

In total, 46 1000-series GMD-1 locomotives were upgraded to 1100-series units. These 1100-series rebuilds were outshopped between 1983 and 1988 and lasted in service as late as 2006.

Most importantly, the 1100s were used nationwide. If you model Canadian railways in the 1980s or 1990s, these GMD-1 locomotives are for you.