Boy that was an odd one.
I am guessing that the freight cars were being ferried to either Cumbres or Antonito, as well as one engine, for a Trains Unlimited Charter that would follow a day or two afterwards. I recall one such trip that picked up extra cars at Cumbres. The trip was with a single engine train from Chama, so they picked up extra cars to make the train bigger at Cumbres.
The cars are definately not for the Friends Work sessions as I had speculated. Sure made an interesting shot. I suppose they still had to stop at Lobato and separate the two engines for the trestle????
Greg