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UP - Natron Cutoff Tunnel 22


West Portal Of Tunnel 22, Contextual View To The Northwest, 135mm Lens. Tunnel 22 Pierces A Ridge Separating Oakridge From Westfir

Photo taken for the Historic American Engineering Record

View photos at Library of Congress

BH Photo #300762



The Southern Pacific Railroad Cascade Route, built as the Natron Cutoff between Black Butte, California and Natron, Oregon was one of a series of major rebuildings and realignments of the original Central Pacific Railroad. Begun in 1905 under railroad magnate E.H. Harriman to replace the original Central Pacific route over the Siskiyou Mountains into Oregon, the Natron Cutoff had to overcome both natural and political obstacles. Stalled by government anti-trust lawsuits against Harriman, by World War I and the ensuing federal takeover of the nation's railroads, the Natron Cutoff finally overcame the rugged Cascade Mountains of Oregon to reach completion in 1927, at an ultimate cost of nearly $40 million. For the purpose of the current project, the Natron Cutoff was found likely to be eligible for the National Register of Historic Places at the state level of significance under Criterion A for its significance in engineering, transportation history, and the economic history of central Oregon, and in the development of the West, and under criterion B for its association with E.H. Harriamn. The Natron Cutoff's period of significance is 1905 to 1945, from the beginning of construction in 1905, through the years of its role in the economic development of the central Oregon, to the conclusion of the railroad's achievements in World War II. Built in 1910, Tunnel 22 is a contributive element of this property.

Tunnel 22 is a 1,199-foot, single track railroad tunnel with concrete portal faces and wingwalls. The semi-circular arched opening is framed in dressed stone masonry voussoirs, the portal has a concrete parapet atop a stone masonry belt course topped by dressed stone masonry coping. A coping of dressed stone masonry blocks tops the stepped wingwalls. As-built, the tunnel was concrete-lined for the first fifty feet in from each portal, with the remainder unlined; the railroad subsequently lined the bore with timber between 1920 and 1945, and has since covered the timbering with shotcrete. The tunnel is on a two-degree, thirty-minute left-hand curved alignment, and carries the tracks of the Union Pacific Railroad's (formerly Southern Pacific) Cascade Route line,

-- Historic American Engineering Record


Tunnel on Union Pacific Railroad
Lane County, Oregon
Open to traffic
Built 1910
- Utah Construction Co. of Ogden, Utah
Total length: 1,199.0 ft.
Approximate latitude, longitude
+43.75389, -122.48798   (decimal degrees)
43°45'14" N, 122°29'17" W   (degrees°minutes'seconds")
Approximate UTM coordinates
10/541220/4844665 (zone/easting/northing)
Quadrangle map:
Westfir East
Inventory number
BH 63557 (Bridgehunter.com ID)


Built 1910 (1,124)
Built during 1910s (9,478)
Lane County, Oregon (103)
Open (39,166)
Oregon (1,135)
Owned by railroad (11,936)
Total length 1000-2500 feet (1,826)
Tunnel (1,193)
Utah Construction Co. (10)

Update Log 

  • October 11, 2014: Added by Dave King


  • Dave King - DKinghawkfan [at] hotmail [dot] com
  • HAER OR-94 - Southern Pacific Railroad Natron Cutoff, Tunnel 22, Milepost 581.85, Oakridge, Lane County, OR