On April 20, 1884, the first train crosses the Snake River on the Northern Pacific Railroad's bridge at Ainsworth, a railroad construction town located at the junction of the Snake and Columbia Rivers in Franklin County. The completion of the bridge links the Northern Pacific's transcontinental line directly to the Oregon Railway & Navigation track down the Columbia River to Portland, and ultimately to Puget Sound.
Although the Northern Pacific intended to (and ultimately did) build its own line across the Cascades directly to Puget Sound, in 1880 it had entered a "traffic agreement" with the Oregon Railway & Navigation Co. (OR&N), allowing the transcontinental company to use the OR&N track along the Columbia. Because the Northern Pacific was not fully committed to the Portland route, it did not immediately build a bridge connecting its track to the OR&N. Instead, the stern-wheel steamer Frederick Billings (named for the NP president), capable of carrying 11 freight cars and an engine, ferried trains across the Snake River at Ainsworth.
When Henry Villard, who already owned the OR&N, took control of the Northern Pacific in 1881, he set out to channel all northern transcontinental traffic onto the OR&N line to Portland, making a bridge across the Snake River essential. In March 1882, D. D. McBean was given a $350,000 contract to build piers and abutments for the bridge, which would be 1,540 feet long. McBean was supposed to complete the work by April 1883, but lacked the resources to do so. The Northern Pacific took over the project, appointing noted diver Ed Spencer as superintendent. Six of the seven piers were completed by the end of 1883, and the final one in February 1884.
Construction of the bridge's iron superstructure, which consisted of a 146-foot Pratt through-truss span, a 346-foot swinging drawspan, four 248-foot Pratt through-truss spans, and a 65-foot deck girder span, began in November 1883. The work proceeded night and day, making for rapid progress, but also for at least one serious injury. By mid-April, all the spans were in place except for the short span at the south end, for which the needed girders had not been delivered. The gap was filled by a temporary timber trestle, allowing the track to be laid.
The First Train Crosses
On Sunday, April 20, 1884, at 9:25 a.m., a train consisting of three cars and an engine driven by C. S. Larison, with various Northern Pacific officials aboard, crossed the bridge slowly from the south. At Ainsworth, another engine and a car with numerous passengers were added, and the train crossed back over the bridge, stopping along the way to take measurements on each span. The test results were satisfactory, and the bridge was declared open to traffic.
The Northern Pacific reported the total cost of the bridge to be $1,135,743. Even before the bridge was completed however, Henry Villard lost control of the Northern Pacific, which was separated from the OR&N and returned to its original owners. The Northern Pacific again turned its attention to building a direct line over the Cascades, leaving the future role of the Snake River bridge and the town of Ainsworth uncertain.
The present day (2003) bridge at this location has been substantially rebuilt.