Thanks to a correspondent on the East Coast for the pictures and information on this line.
The bridge which I found in the backcountry a few miles above Tetonia, just
13 miles SW of the outer SW corner of Yellowstone NP, and just 1 mile west of the outer boundary of Targhee National Forest, spans Bitch Creek at a height of about 134 feet above the water below, and is truly majestic. I have included a few fotos. Most were taken from the creek bank up from the NW corner of the bridge, and one was taken from the deck of the bridge, showing the terrain to the west.
Originally part of the Oregon Short Line Railroad, this line was a spur off of the UP at Ashton, ID, traveling southeast through Marysville, Grainville, Drummond, France, Lamont, and then south to Judkins, Fell, Tetonia, Talbot Jct, Driggs, Fox Creek and then ending at Victor. There was a spur from Talbot Jct to Talbot. Today, the Eastern Idaho Railroad operates from Idaho Falls to Ashton, with part of the branch to Victor being used in and around Ashton.
From the person who explored this line:
"I recently spent some time exploring an abandoned RR bridge in eastern Idaho, not far from Jackson, WY, Yellowstone National Park and Targhee National Forest, listed on topo maps as the "Union Pacific Railroad". The abandoned Union Pacific line of which the bridge is a part runs pretty much N-S from below Victor, ID, up to above Tetonia, ID, where it starts to bend almost 90 degrees to the west-northwest. The line has been abandoned, and the abandoned properties -- except for a few which reverted back to the original landowners via abandonment clauses -- were brought by the state and the counties to convert to Rails to Trails. That has been completed in Victor and Driggs, and further south and east (i.e., toward Idaho Falls), but above Driggs, and particularly around Tetonia, the conversion project has not yet been completed. The rails and ties have been removed from the rail bed, and signage and fence barriers have been erected to keep vehicles off the bridge (but which allow hiker/pedestrian traffic), but the trails conversion project has never been completed in this region because two or three abandoned RR properties just north of Driggs reverted back to the original owners and the property owners are refusing to sell the property back to the state and county, thus causing an interruption in the continuity and contiguity of the trail."