Maybe they simply took the extra caboose to Durango thinking they might use it there for future work trains, or who knows what. After that the only way was by highway.
In our last visit in 1968, we chased 483 with 493 as the helper from Chama up the hill to Cumbres. From there 483 took the train as 493 being the helper went on ahead. There were two cabooses on this
first eastbound for 1968 from Chama!!! I think I posted a shot at Cumbres Loop showing this in the past. I know my brother and I hiked down there from Cumbres.
Greg