I had a chance to visit the MUT Lines in the mid-80s when I lived in Dallas. It was like seeing the hobby's history in North America--not only was Cliff a model railroad pioneer, he knew many of the other pioneers like John Allen (he had some GD locomotives in his layout room).
Cliff also used Baker couplers--another connection the the past. (At least, that's what I think they were.)
Since the MUT Lines was pre-Internet, there seems to be very little about it on the Web. That's too bad.