FAIRBANKS — By 1921 the Alaska Railroad was tantalizingly close to completion. The 470 miles of track that would carry trains between Seward on the Kenai Peninsula and Fairbanks in Interior Alaska was essentially complete. The only hindrance was a 700-foot gap across the Tanana River that took an additional two years to bridge.
For seven years, the Alaska Engineering Commission (AEC), the federal agency responsible for constructing the railway, had been rebuilding the dilapidated Alaska Northern Railroad line from Seward to the head of Turnagain Arm and extending tracks northward to the Susitna Valley and on through Broad Pass to Nenana. By 1921, the line between Seward and Nenana was complete.
As part of its construction efforts, the AEC had purchased the bankrupt Tanana Valley Railroad (TVRR) in 1917. After acquiring the line, the AEC ran tracks southward from Fairbanks to the north bank of the Tanana River, across from Nenana.
When the Tanana was ice-free, the AEC provided ferry service across the river. It operated numerous boats during construction to transport passengers, freight and building materials across the river. After freeze-up, when winter ice was thick enough, the AEC laid railroad tracks over the river ice to the south shore.
Before a bridge at Nenana could be built, a lengthy inclined wooden trestle (later replaced by earthwork) was constructed up to bridge height, and a 420-foot steel-truss viaduct was erected from the trestle to the south pier of the bridge. (The trestle separated Nenana’s Native village from the white man’s town, and the viaduct allowed passage beneath it between the two communities.) Both the approach trestle and viaduct were completed by August 1922.
The bridge across the river was constructed in 1922-23. It was designed by Ralph Modjeski, a Polish-born American civil engineer who was one of the pre-eminent bridge designers of that era. Modjeski was directly or indirectly involved with the design and construction of almost 40 bridges scattered across the United States, including the Mid-Hudson Bridge in Poughkeepsie, New York, and the San Francisco-Oakland Bay Bridge.
The Tanana River bridge was fabricated and assembled by the American Bridge Company. When built, the 700-foot long single-truss steel bridge was the longest truss span in the United States. Matthew Reckard’s 1999 article about the bridge in the Ester Republic states that it is still the third-longest simple truss in the nation and the longest span of any kind in Alaska.
Modjeski was a pioneer in using reinforced concrete for bridgework. Numerous small piers to support the viaduct and two massive piers to support the bridge were formed of poured concrete, five years before Cap Lathrop built the first poured concrete building in Fairbanks.
With the bridge piers completed by October 1922, workers sank pilings into the river bottom to support a wooden falsework trestle across the river. The falsework, brought up to bridge height, is what supported the steel railbed as it was constructed and as the truss-work above was added.
By January 1923 the new bridge was essentially completed, including wooden decking and rails. The first train rolled across the bridge on Feb. 9, 1923.
With completion of the bridge, President Warren G Harding traveled to Alaska to drive in the ceremonial golden spike at the north end of the bridge. According to an article on the AlaskaRails.org website, on July 15, 1923, Territorial Gov. Scott Bone inserted the 14-carat spike into a pre-drilled hole and President Harding tapped it home. The spike was then replaced with a regular iron spike. The golden spike was presented to Col. Frederick Mears, chairman and chief engineer of the AEC and the bridge’s namesake.
Ray Bonnell is a freelance artist, writer and longtime Fairbanks resident. See more of his artwork at www.pingostudio.us.
• Alaska Engineering Commission photographs of Tanana River bridge construction. Anchorage Museum of History & Art. Library & Archives
• “Golden Spike.” John Combs. on AlaskaRails.Org website. 1997
• “Railroad in the Clouds: The Alaska Railroad in the Age of Steam, 1914-1945.” William H. Wilson. Pruett Publishing. 1977
• “Tanana Valley Railroad, the Gold Dust Line.” Nicholas Deely. Denali Designs. 1996
• “The Mears Memorial Bridge.” Matthew Reckard. in the “Ester Republic.” 1999