I tell what I know and it is all suspect. We got 3 of these red, white, & blue locos at one time from a Pittsburg, PA area steel mill. I will see what I can find out about the details from our other members but I think it was Teledyene Corp. However, 2 of the Plymouths (one of which is yours) were larger than the third-which is the one we kept and re-gaged. we cast our own brake shoes locally and the engines is just a common Cummins 4/71. The 2 we let go were picked up by Plymouth and then were sold at an auction when Plymouth folded. We had heard that one wound up out west. Good to see a photo of it! I wonder where the third one got to?
WW&F has a similar unit that was one of several that came from Carpenter Steel in Reading.
Todd