I'm modeling that train in 1972. I had custom decals made for it so that I could do up 30 cars. I did the artwork but DM did the printing.
Back in the 80s research was a bear, but I knew that the way Roundhouse painted their unit train hoppers was all wrong.
Cars were black, the yellow end had a black herald. I wasn't sure then, but I am now, that the car lettering on the black end was YELLOW, not white. That was a mistake several manufacturers have made. That may have changed at some point, but I've seen enough color photos now to finally satisfy myself I got it right then. And I individually numbered every stupid car, did that during my lunch hours at work. I was seeing 749.... in my sleep.
That was the York Canyon (symbol YK/KY) unit coal train from French, NM to Fontana, CA. It was one of the very first trains of its type, started about '68. It started out with the Alco RSD15's, but went through SD24's, SD26's, SD39's. It always used remote mid-train helpers on the loaded runs, during the Alco years it was six on the front, four in the middle, with a B-unit converted to an RCE car with the center 4 units. Empty trips put all ten units on the point. Extensively documented in McMillan's first book, but not in color.
To my knowledge those cars were never used on anything but that movement as long as the unit train lasted. There were many unit trains since, even on ATSF, but that was a landmark train and one of the longest unit train movements ever done at that time.
