I have the MTH GE 44-tonners in that U.S. Army scheme as well as Milwaukee Road. It’s all diecast metal. Great model.
The Milwaukee Road version did hesitate going through a switch on my O-27 home layout, but only in one direction and was not a problem if I turned it around and ran it through the switch in reverse. The Army version has no problem in either direction on that same switch. Go figure.
Photos of both running on the club layout: