Probably nothing against NdeM, but if I remember right, they came in twin packs. One would be a rare sight on most US lines, two in the same train was probably unheard of in most of the country. Run one, strip and repaint the other.
OFF TOPIC: What I would like is an NdeM boxcar suitable for international service in the early 1970s. Atlas has a very nice one, but it's old enough that it probably wasn't in US interchange service. MT made a 50 ft car suitable for the late 70s, but it's too modern for me.