As the light branches were abandoned or rehabilitated, the bulk were upgraded with new fuel tanks and Flexicoil B-B trucks and assigned to yard and transfer service. In 1988/89, 39 GMD1s were remanufactured by CN as GMD 1Us, 12 emerged with B-B trucks and continued to run long-hood-forward, while the others retained their A1A trucks and were converted to shorthood-forward operation.[2] On April 19, 2021, CN's last GMD-1 was retired from revenue service.[3]
^Distinctive GMs get second lives Trains December 2010 page 18
^GMD1's reign on the plains comes to an end Trains August 1999 pages 32/33