This combination truss is not mentioned in "Conveniences Sorely Needed" either. However the book does have a photo showing that the previous Scenic Bridge in Mineral County was a similar combination truss as well. (Page 46 if you have the book). Sadly no info is provided on the date/builder however.
Nice work David. Happy Bridge Hunting!
WOW! This is an awesome discovery!
This bridge looks very similar to the bridge over the same river near Coburg. https://bridgehunter.com/mt/blaine/coburg/
This bridge is not listed anywhere I could find. It is located about 7-8 feet east of Bridgehunter #22973. Up to this point, no history available. The sign on top of the bridge is so rusted it is difficult to read but looks something like - "-ont-omery & --- 1--7". At least that's what it seems to read. It has been abandoned a long time and a couple of the beams that supported the deck are deteriorating and coming apart.