Construction of the Bridge Willamette River Swing Truss Railroad Bridge, Portland Oregon

The Vancouver-Portland bridges were designed by the internationally recognised engineer, Ralph Modjeski, whose reputation as a major bridge designer began with the building of the Thebes Bridge (1904) across the Mississippi River at Thebes, Illinois. He designed the McKinley Bridge (1902-1910) in St. Louis, the Ohio River Bridge (1914-1917) at Metropolis, Illinois, and the Crooked River Bridge (1912) near Redmond, Oregon, as part of his long association with the railroads.

Modjeski began his investigation of the Burlington Northern Railroad Bridge in September 1905. He met with Mr. Benjamin L. Crosby, principal assistant engineer for the Pacific Division of the Northern pacific Railways and examined the proposed crossing of the two rivers and the alternative routes in between them. He approved of the alignment previously surveyed by the railroad with two alternatives for crossing the Willamette River, one more north of the final route proceeded around St. John's Point, and the second in the direct line of the Columbia River Bridge through Portsmouth, the route adopted. Modjeski endorsed the previously-determined Columbia crossing because,
"...the permission of the War Department will probably be more easily obtained for building a bridge on the site which has been approved once before than in an entirely new location. Another consideration, although perhaps of minor importance, is that this location would permit the use of the present pier, and a corresponding saving in cost of some $60,000 to $80,000."
Modjeski also recommended the double tracking of the right of way and bridges as being more cost effective in the long run.

Preliminary construction work began in November 1905 at offices opened at the Vancouver end. Plans were submitted to the War Department of January 1906 and approved a month later. Work began on the Columbia River sections while negotiations with the Port of Portland were being concluded to fix the character and size of the Willamette River draw span. The Willamette River draw span as approved was the longest swing span in the world at that time. The conditions established by the Port of Portland for the design and operation of the new bridge were generally in conformance with the standards of the Secretary of War (Army Corps of Engineers) for the design of bridges across navigable waterways. The Port of Portland made two additional requirements: A higher clearance above low water level, putting the Portland bridge at a 16.62 foot higher elevation than the Vancouver bridge. The difference in elevation was accommodated by a slight incline grade through the Portsmouth Cut. The bridges were to be made available to competing railroads. Port of Portland approval was given in April 1906. War Department approval was given in June 1906.

Construction work on the Willamette Bridge began in August 1906. Construction on the bridges and their approaches took two years. Superstructures were completed in July 1908, machinery work completed that October, and the first passenger train, Mr. James J. Hill's Special, passed over the bridges on November 5, 19O8.