Five examples of the slightly different M-420R were built for the newly-independent Providence and Worcester Railroad (P&W) from 1974 to 1975 using trade-in parts and Type B trucks.

Both M-420TR variations bore little resemblance to the other models, with a lowered hood, shorter frame and end-cab design.

CN M-420 3502 was hoisted off the rails by crane and rolled along a street in Boucherville in order to provide power in the community.

[6] M-420 3508 was also lifted from the tracks to provide power to a school being used as a shelter, but problems prevented this from happening, and 3508 remained on standby.

Following their retirement from CN, P&W, and BC Rail, some M-420 units were scrapped, but many were sold to shortline railways across North America for continued service.

Larger shortlines such as Omnitrax have begun to scrap or sell their MLW units as a result of increased maintenance and reliability issues.