Concerning the make up of eastbound trains at Cumbres, I think the crews threw together whatever was up there, did an air test and left. There may have been some attempts to block the trains, but I doubt it. Another factor to consider is the downgrade starts in the first right hand curve after the present highway crossing. Switching out a long train out at the east end of the long siding at Cumbres would be difficult with one engine. I've seen movies of 484 switching the two halves of an eastbound together out at the east switch and they were having a tough time backing 20 loads. I believe the helper usually took off for Alamosa as soon as it was released from the train as that crew was paid a lesser rate for being the helper crew.
One must also remember that in the later years, there was very little "local" traffic. Traffic to and from Alamosa, consited of cars were for Chama (tanks for Gramps Oil, flats and boxes for the sawmill) Durango (small amount of local traffic) or Farmington (gas pipe, drilling mud, etc). There was a small abount of coal out of Monero and some gas field business got set out in Ignacio and in Aztec on the Farmington Branch. But by and large most trains didn't do a lot of local work. During the harvest season in the Valley, NG trains did SG local work with these cars on the head end.
Knowing what I do about how road crews do thier business, if there is a switch crew do sort out their mess at the other end, they really don't care how the train is blocked when it gets there. I would guess that trains coming into Chama from either end would have the Chama setouts blocked where they could be set out easily (front or rear) - remember there was no switch crew in Chama, the road crews did the switching. Headed west toward Durango I would imagine the "short" work would go on the head end, followed by the through cars for Durango. Farmington cars would go on the rear.
Headed east, the train would be cut in 2 or 3 sections depending on tonnage and reassembled at Cumbres. There being no local work between Cumbres and Antonito (other than occasional company business like ties, coal or ballast). There was no need to block the train. If there was SG work to do, they would pick up SG idler cars in Antonito, and do whatever local work was needed on the way in.
Photos from the early 1950's show that hill turns out of Chama tended to put the helper in the middle if there were a lot of wooden idler flats made from high side gons in the train (they tended to buckle). With the development of more steel cars and idlers built from stock cars and box cars in the mid 50's, folding cars were not a problem and the helpers were mostly on the rear.
Gramps Oil appearently was not considered too hazardous as there are lots of pics with loaded tanks both directly ahead and immediately behind locomotives.
Most stock movements were handled as seperate trains. Although there are shots of other cars mixed in with stock trains. As these cars were "hot moves" they generally stayed blocked together as they were all headed to the same spot - and headed there quickly. Of course empty stock cars could be found going anywhere in a consist.
