Tobin Bridges, transportation infrastructure in California

The Tobin Bridges are two bridges over the North Fork Feather River in Plumas County, California. The upper single-track railway bridge, built in 1909, carries the Union Pacific Railroad's Canyon Subdivision and crosses over the lower road bridge. The road bridge, completed in 1936, carries two lanes of California State Route 70. The railway bridge has a 79.2 m truss span and a 15.2 m beam span; the road bridge has a single 88.4 m K-truss span.

The Western Pacific Railroad built the single-track railway bridge in 1909 as part of its 1,500 km Feather River Route between Oakland and Salt Lake City, a rival to the Southern Pacific's Overland Route. The road bridge was completed in 1936 for the Feather River Highway, later California State Route 70; its north abutment sits directly beneath the railway bridge's west abutment. The WP was absorbed by Union Pacific in 1982.

The bridges appear in Plumas County's "7 Wonders of the Railroad World", a local list that draws railfans to the Feather River Canyon. The name comes from the nearby census-designated place of Tobin. The two decks sit almost on top of each other: the railroad bridge passes over the highway, which runs beneath it along the river.

The road bridge carries two lanes of California State Route 70 on a 7.3 m wide deck, with the northern abutment set directly beneath the western abutment of the rail bridge above. Average traffic in 2009 was about 1,345 vehicles a day. The rail deck sits overhead, so drivers pass under the railway.

The road bridge's north abutment sits directly beneath the west abutment of the railway bridge, so the two structures nearly touch at the river's west side. The rail bridge also passes over Highway 70, stacking rail above road above water in one spot.