"San Juan" power question

Guessing from what El Coke wrote about the steam heating system, they must have installed a low pressure system, these use more steam than the high pressure systems, but the can be better adjusted (temperature) than the high pressure systems. Considering that the San Juan was only 4-6 car train, I wonder why the crews complained about the loss of steam for the heating.
Are there any traces of the second air line or the heating system left on the engines? I'm quite sure the D&S removed the stuff from their locos and cars, as the heated D&S cars use individual propane units, but there could be evidence of both systems in the C&TS engines left.
Boris