Carlin Tunnel

Carlin Tunnel

The four western portals to the Carlin Tunnel; the two Interstate 80 bores are on the left and the two railroad bores on the right.
Overview
Line	Overland Route
Location	Near Carlin, Nevada at Tonka rail siding
Coordinates	40°43′18″N 116°00′51″W / 40.721665°N 116.01408°W / 40.721665; -116.01408Coordinates: 40°43′18″N 116°00′51″W / 40.721665°N 116.01408°W / 40.721665; -116.01408
Route	I‑80
Operation
Opened	1903 (original railroad bore); September 25, 1975 (I-80 bores)
Operator	Nevada Department of Transportation Union Pacific Railroad
Traffic	Automotive and rail
Character	Interstate Highway system (two bores) Passenger and freight rail (two bores)
Vehicles per day	10000
Technical
Length	0.3 miles (0.48 km)
No. of tracks	double track
No. of lanes	4 lanes in 2 tubes
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Operating speed	75 miles per hour (121 km/h)
Highest elevation	4,950 feet (1,510 m)

The Carlin Tunnel is a collective name for a set of four tunnel bores in the Humboldt River's Carlin Canyon, east of Carlin in Elko County, Nevada, United States. The two railroad bores were constructed for different purposes at different times, while the two highway bores were constructed concurrently, all with the goal of bypassing a sharp bend in the river. Currently, two of the bores carry Interstate 80, while the other two bores carry Union Pacific Railroad's Overland Route and Central Corridor. Bridges over the Humboldt River are adjacent to both portals of three tubes, including the two freeway bores and one of the railroad bores.

The first bore was constructed by the Southern Pacific Railroad in 1903 as part of a straightening of the First Transcontinental Railroad, prior to this time the railroad followed the curved river through the canyon. The second tunnel was constructed by the Western Pacific Railroad for the Feather River Route. The modern Union Pacific Railroad, which acquired both of these railroad companies, has combined the former competing lines into a dual-track directional running main for uninterrupted traffic. The former Southern Pacific bore crosses the Humboldt river at each portal, similar to the freeway bores, while the former Western Pacific bore does not cross the river at the tunnel portals.U.S. Route 40 was originally routed on the old railroad grade through the canyon. With the planned construction of Interstate 80 through the area, a third and fourth bore was constructed to accommodate the expected traffic increase and higher traffic speed; these were completed and opened on September 25, 1975.