If you have 5 minutes or so, take a look a the highest railroad bridge in America. The High Steel Bridge (or South Fork Bridge) just a few miles north west of Shelton WA. Along with the somewhat lower but maybe better known Vance Creek bridge.
Both were completed in 1929 by the American Bridge company. The High Steel Bridge is either 365' high (by many good sources) or 420' high according to the U.S. Forestry service. 750 tons of steel and 685 feet long. It saw it's last train in 1947 and in 1950 was converted to a road bridge (FS2340). This bridge is on the National Register of Historic Places.
The Vance Creek bridge is 347' high and 800' long. It saw train service much longer than it's taller sibling (1970's) and was placed on the National Register of Historic places in 1982. It now serves as the text book example of an attractive nuisance. It's owner Green Diamond Resources, removed some of the ties on the north end to prevent (reduce) the number of people trying to walk and climb the bridge.
Simpson Bridges