@PRRMP54 posted:Atlas/Roco offered a similar (Plymouth WDT) two-rail switcher in the 1970s. It is a good runner and quite powerful without the use of traction tires.
The Atlas model was a six wheel Plymouth WDT.
AHM offered the four wheel Plymouth MDT version. I recall it being a little oversized:
Both locomotives were 2 Rail Scale DC.
Rusty