Not only is the line disconnected at both ends, but the RR formerly connected to at the Leadville end, while still intact, is no longer operating (former D&RGW Tennessee Pass/Royal Gorge line). I can't imagine that the small amount of concentrate Climax'll produce would induce the UP to reopen that part of the line.
Interesting to hear the mine may reopen, though. I was a miner at Climax for a short time in the early '70's, just before things started going south for AMAX. At the time, it was the largest underground complex in N America. The job was "entertaining" enough that it was what finally convinced me it was time to quit goofing around and go to college.
Climax was also the first place I ever swung a spike maul - doing minor track work during my orientation period down on "600" level.
The RR underground on "Stork" level where I worked most of my time there was quite the operation. It was powered by 20 and 30 ton electric motors, and dispatched by a guy who was physically located underground at the first switch at the start of actual workings - hence he was called "One switch".
Were the mine to reopen, however, I doubt there'd be any rail operations. I expect most mining would now be in the open pit rather than underground, and entirely conveyor and truck based.
Scott