Here is the top of Rollins pass The Rio Grande's route thru the Rockies. The 4 percent grades and heavy snows got so bad that the pass was closed more of the year than it was open. It was a mix of switchbacks and snowsheds requiring lots of power for even small trains and was hell
to operate.In the 20's The railroad built the Moffat tunnel thru the mountains instead of over the summit. Still a magnificent ride thru the mountains, but not the heartbreaker it was originally. Amtrak's San Francisco Zephyr runs there today. It's consdered their most scenic route