Thanks John. Yeah, the only freight train I saw on the 12th was June 13, 1967. 487 left Chama solo with 42 cars and I chased (more like crept as they stopped often to dump ballast - first train of the year!) the train to Dulce where they picked up some more loaded ballast cars and I had to leave the train there.
Later that night the 487 and 483 came in from the East. I assume the 483 backed out of Durango to Gato or Arboles to help 487 over Falfa.
Of course anything we saw in these last years may well have been uncharacteristic of 30s-40s-50s operations. I've been digging into Jimmy's trainsheet posts but the data is unclear where the helpers cut in and out for that stretch.