Blair Subdivision

The Sioux City and Pacific Railroad was a railroad in the U.S. states of Iowa and Nebraska. Built as a connection from Sioux City, Iowa to the Union Pacific Railroad at Fremont, Nebraska, it became part of the Chicago and North Western Railway system in the 1880s, and is now a main line of the Union Pacific (UP). The east-west portion from Fremont to Missouri Valley, Iowa, is the Blair Subdivision, carrying mainly westbound UP trains (most eastbounds use the Omaha Subdivision), and the line from California Junction, Iowa north to Sioux City is the Sioux City Subdivision.

The Pacific Railway Act of 1862 defined a network of branches that would begin at the Missouri River and join the main line of the Union Pacific Railroad in or near Nebraska. The UP was required to build the branch from Sioux City, but an 1864 amendment released the UP from this obligation, allowing any railroad arriving at Sioux City from the east, or any newly incorporated railroad, to construct the line and gain the associated land grants. The Sioux City and Pacific Railroad was organized for this purpose in August 1864, and soon came under common ownership with the Cedar Rapids and Missouri River Railroad, a land-grant company, leased by the Chicago and North Western Railway, that completed its road across Iowa to Council Bluffs in April 1867. To build the portion in Nebraska, the Northern Nebraska Air Line Railroad was incorporated in June 1867 and merged into the Sioux City and Pacific in September 1868.

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