Station on the west bank of the Chicago River. The railroad built a permanent depot at the corner of Canal and Madison streets in 1861. On April 7, 1874 five railroads agreed to build and share a union station just north of the original Pittsburgh, Fort Wayne, and Chicago Railroad station site at Van Buren Street. These railroads were: Pennsylvania Company (a subsidiary of the Pennsylvania Railroad) Chicago, Burlington and Quincy Railroad (Burlington Route) Michigan Central Railroad Chicago and Alton Railroad Chicago, Milwaukee and St. Paul Railway (The Milwaukee Road) The Michigan Central, which had previously been using the Illinois Central Railroad's Great Central Station, soon decided to back out of the agreement, and continued to use the Illinois Central Depot. The Chicago and North Western Railway, not part of the original agreement, considered switching to the new station from its Wells Street Station but deferred instead. In 1911 it built the Chicago and North Western Passenger Terminal for its operations. The remaining four original companies used the station when it opened in 1881. The headhouse of the Union Depot, a narrow building, fronted onto Canal Street and stretched from Madison Street to Adams Street. Tracks led into the station from the south, and platforms occupied a strip of land between the back of the headhouse and the bank of the Chicago River. South of the station, Adams, Jackson, and Van Buren Streets rose over the tracks and the river on bridges. The station, along with its successor, was effectively two back-to-back stub-end terminals. Virtually all trains arriving would terminate there, and passengers traveling further would need to change trains. Replacement Growth in passenger traffic, as well as a civic push to consolidate numerous railroad terminals, led to a proposal for an enlarged Union Station on the same site. The second Union Station would be built by the Chicago Union Station Company. This was a new company formed by all the railroads that had used the first station, save for the Chicago and Alton, which became a tenant in the new station. The Pennsylvania Railroad, then the U.S.'s largest railroad company, planned and directed the project. The architectural firm was D. H. Burnham & Company (known for its lead architect Daniel Burnham, who died before construction began). The successor firm of Graham, Anderson, Probst and White completed the work. Work began on the massive project in 1913, and required purchasing