My understanding is so long as the San Juan was running, as well as reasonably frequent freights, snow clearing was rarely a big deal, except on those reasonably rare occasions a really big storm came along. The frequent trains would have kept the mainline reasonably clear, but probably the sidings needed to be plowed occasionally. An interesting period would be after the San Juan quit and freight traffic peaked in the mid-60's, meets apparently were common at places like Cumbres, Toltec, Sublette, and Big Horn. While there were a lot of freights, I would guess the loss of the daily passage of two passenger trains made snow clearing more of an issue, and the sidings had to be kept passable. By the early 1960's there were few if any meets west of Antonito, so the need to clear sidings as passing tracks was presumably minimal. Probably far more important was clearing sidings so that bad order cars could be set out.
JBWX