I got the MTH PS2 version on eBay. Good price with very little run time. It's the homeliest engine in my collection but I really like it. All diecast body, very heavy. One motor. Runs smooth and pulls well going forward. Not so much in reverse. Historically I had no idea that GE and Ingersoll Rand made quite a few of these little very first diesel + electric traction motor engines. In the photo below I removed the front electro coupler and replaced with an open coupler. This turns the engine into a "pushing" switcher on my layout that can engage car couplers on curves and move them to connect with a bigger engine or consist.
What is interesting to me is the similarity to the MTH GE 44 Tonner. I have two of these. It has (I would think) a single motor. And unless the two single roller pickups are kept clean and the non traction wheels kept clean and polished these engines will drop power and shut down at some of my switch locations. The Boxcab only has two pickup rollers but only two traction tire wheels. And so far has been impossible to stall. Really shows how the 44 Tonner has more of a return outer rail connection problem than a pickup roller problem.
NOTE: prototype photo deleted due to copyright per OGR TOS.