The standard gauge tank at French Creek was there in the standard-gauge era for one reason--to provide water for the rotary snow plow, which
was a water eater. In due course the rotary ended up at the Colorado Railroad Museum.
I suppose that, were the #638/#641 to do a lot of switching at Climax or they were plowing snow, a stop would be made at French Creek. But I can't imagine that these locomotives would have consumed all of their water running the 14 miles between Leadville and Climax.
Back in my stupid youth (I'm brilliant now! I'm also humble!), I walked the rail line from Climax down to Leadvile. Got lots of beautiful pictures, saw ties with spike/plate marks for 3'-gauge--and nearly ruined my feet! I limped into the Pizza Hut and set a world record for how long it could take an individual to consume a pizza. I can't remember how I got back to my car.
Mike