Not sure if you have ever been in the area or not, but the SVRy came up from Praire City on the East side of Hwy 26. Near the summit there is an Interpretive site with a path leading you down a short distance to the downhill leg of the original switchback. The USFS and SVRR have set up a few panels track and a switch over the original roadbed so people can get a feel for how steep it was and how it worked. From the first switch going up hill, the roadbed is covered by a fill for Hwy 26. There are several metal panels with SVRy history.
On my way to McEwen, Missy (my dog) and I frequently stop there and hike down to the tracks. There are still a few original rotting ties on a portion of the road bed just before Hwy 26 engulfs the old roadbed.
dan