The Northwest Corridor is one of Continental Rail's major mainlines. Constructed in phases from 1869 to 1892, it was electrified and upgraded in the first half of the 1920s to provide higher service levels and effectively compete with US Route 101, which it parallels for much of its route. The line runs from Tijuana, Baja California, Mexico to Vancouver, British Columbia, Canada, with 99% of its route being in the United States in California, Oregon, and Washington.
The first segment of what is now the Northwest Corridor was built in 1869 between San Jose and Gilroy, California as part of the railroad's initial form, the Central Valley Railroad from San Francisco to Fresno. The first extension was built in 1871 from Santa Clara to Sacramento via Oakland, making the connection with the Transcontinental Railroad. The next extension came in 1880, when the railroad renamed itself from the Central Valley & Lake Tahoe Railroad (renamed in 1875 after the completion of the Sierra Line) and extended south out of Gilroy to Los Angeles, and again in 1889 from Sacramento to Seattle, Washington, completing the route in its current form.
In 1892, the northern part of the line was extended across the Canadian border to Vancouver. Although the line was further constructed north towards Whitehorse, the Northwest Corridor's official northern terminus is Vancouver. In 1906, as part of Continental Rail's extension into Mexico, the "Western Line", as it had come to be known as, was extended to Tijuana, Mexico; like the Vancouver extension, Continental Rail continued building southward towards Mexico City, but the official southern terminus of the NWC is Tijuana.
Electrification and Modernization
The plan to electrify the Western Line originated in 1904, with a view towards increasing speed and frequency to compete, initially, with coastal steamships. After years of surveys and studies, Continental Rail gave the greenlight to begin the project on April 6, 1918. The plan, however, was put on hold several hours later when the United States entered World War I and Continental Rail came under the control of the United States Railway Administration (USRA).
Days after the signing of the Treaty of Versailles, work began in earnest on the Northwest Corridor. Among the improvements made, aside from total electrification, was resignalling the entire line to run on Centralized Train Control, quadruple-track sections to allow express trains to overtake slower trains, and new yards at important junctions.