An earlier thread discussed the trackage at Cumbres. That got me trying to remember how the switching was done to assemble the big trains for the downhill run to Alamosa. The trains I saw in the early 60's often were at or close to the 70 car limit.
Several things complicate what otherwise might be a simple question: there wasn't all that much track at Cumbres , the helper from Chama was cut in ahead of the caboose, the helper had to get around the train to run light to Alamosa ahead of it, and finally the whole place was on a grade so the ability of the road engine to shove cars uphill might have been limited.
Here's my theory, based in part from reviewing some of my old pix. This assumes the cars from Chama have come up the hill in three cuts, two Cumbres turns on day one, and then a third cut with the through train on day two. That seemed to be a typical patter in the early 60's.
After the train from Chama arrived and the road engine took water, it and the helper would pull the train forward to spot the helper for water. At that point the train would be cut off from the helper and pulled down the main to just clear the east switch to the north siding. At that point the road engine would cut off and use the crossover to duck into the west end of the south siding. That would leave a clear path from the north siding to the mainline going east. The road engine would tie into whatever cars were set out on the west end of the south siding and begin pumping up the air.
After taking water, the helper would pull down to the west switch to the north siding, cut off the caboose, and run around the train on the north siding, get on the mainline and say sayonara to the road engine and train crew, and head for Alamosa (and a relatively early quit).
On the caboose the air would be bled off and the handbrakes released and being just east of the summit it would role down the mainline to a joint with the rear of the train.
After the helper was gone and the air pumped up on the cars in the west end of the siding, the road engine would pull the cut through the crossover and shove it back (uphill) to a joint with the rear of the train on the mainline. The road engine would then go down to the east switch to the south siding, couple onto whatever cars were on the east end of the south siding, pump up the air, pull them out onto the mainline, and then shove (uphill) to a joint.
That would put the whole train together, so the final step would be an air test and then off to Alamosa.
If any readers have gotten this far they are either asleep or as fascinated by this trivia as I am.
Anyway, I'm wondering if anyone out there in the real world can confirm how close the above is to reality.
JBW