As far as I know, the third rail ended at about the city limits heading north (to GJ). The "Y" was three railabout 1/4 mile past the fork going to Ridgeway/Ouray and the other fork heading to the Black Canyon. I'm sure there were end of third rail signs but I have not seen any photos. The first time I lived in Montrose was 1954 and I was tiny. My Father was on the crew converting the line to Ridgway to standard gauge and the narrow gauge days were over by then.
Jerry