Interesting article! The day before we actually rode, we happened to drive up from Trinidad on Hwy 12 and saw the train at the scheduled lunch stop at La Veta. The crew was occupied re-railing the front wheels of the lead locomotive. The article mentions that incident.
SL&RG passenger equipment consisted of two LIRR commuter coaches and an open-air heavyweight coach. I wouldn't trust the AC in the two LIRR coaches either. My advice: Stay in the open-air car. [Actually we took refuge in the closed cars on the dusk return to Alamosa from Antonito because of the mosquitoes!]