The S Bridge on the Coeur d' Alene Branch of the NP above Mullan, Idaho crossed Willow Creek. Directly above or south of the S Bridge there is another crossing of Willow Creek. That crossing is fill. Of course, that right of way across Willow Creek is now dirt road. Periodically I encounter holes in that road 1-2 feet deep extending down. Has anyone ever read if that is/was a filled in trestle bridge?
Have you tried the NP/GN archives site, or NPRHA.org, to see what track maps they might have available? Right of Way maps may show were there is a missing bridge number due to a fill. Or when a newer culvert is placed, an out of sequence number, fractional number, or sub-lettering.
Railroads Through the Coeur d' Alenes shows a photo from the Nellie Stockbridge Collection taken from the west end of the S Bridge looking south and there it is. A trestle. Have had that book for 30 years and just noticed it. Thanks all.