ping: train experts
What is the purpose of the third rail displayed in these pictures below (which is the RTD light rail train system of Denver, CO)?
I doubt they supply electricity as there are overhead wires on those tracks. After the recent blizzard, I've noticed that those third rails were still covered by snow, leaving me to believe they aren't in contact with the trains.
It's not a dual-gauge railway either as this third rail only seem to exist within the boundaries of certain station (couple hundred yards at most). There isn't any third rail in the stations located downtown.
Any ideas?
I doubt they supply electricity as there are overhead wires on those tracks. After the recent blizzard, I've noticed that those third rails were still covered by snow, leaving me to believe they aren't in contact with the trains.
It's not a dual-gauge railway either as this third rail only seem to exist within the boundaries of certain station (couple hundred yards at most). There isn't any third rail in the stations located downtown.
Any ideas?
http://en.wikipedia.org/wiki/Third_rail
The Blue Line of Boston's MBTA uses third rail electrification from the start of the line downtown to Airport, where it switches to overhead catenary for the remainder of the line to Wonderland. Dual power supply method was also common on these few US interurban railways that made use of third rail (all closed). Thanks to being able to run under wires, they could reach downtown by using streetcar (trolley) infrastructure.
It's a guard rail to help prevent derailments in the stations, where people on the platforms could be injured or killed.
A powered third rail would not be down on the crossties with the other rails. It would be raised up on insulators, and in the stations it would on the side of the tracks away from the platforms.
A powered third rail would not be down on the crossties with the other rails. It would be raised up on insulators, and in the stations it would on the side of the tracks away from the platforms.


