The milepost you state on the North Fork Branch is correct. The bridge is just west of the small hamlet of Austin, Colorado. I used to live in that area. About 8 years ago, the UP renumbered the mileposts on the North Fork Branch. Originally, they went upward from Delta (M.P. 375.?--measured from Denver via Pueblo, Salida, Gunnison, Cerro Summit, and Montrose). When re-numbered, the mileposts on the North Fork Branch now begin at 0.0 in Grand Junction and go up from there towards Delta, Paonia, and Somerset. Interestingly, the UP left the original mileposts on the branch from Delta to Montrose (now called the Montrose Industrial Lead). UP is currently building a new track that will bypass the Delta yard to increase train speeds through Delta. A highway bypass is also planned on an alignment almost on top of the Montrose Branch trackage through town. This may spell the end of the Montrose Branch. Too bad, it was a fun place to watch trains, and the Montrose local has a lot of charm.