Between 1892 and 1906, Chicago had three cable car tunnels under the Chicago River. Two were built for pedestrian and horse traffic and later converted, the third was built specially for cable-cars. After cable service ended they would be used by electric streetcars. By 1900, Chicago had a cable-based transit system that carried 80 million passengers a year, but all cable routes leaving downtown to the North or West had to cross the navigable Chicago River. Heavy shipping traffic required movable bridges, which cable lines couldn't cross. Two existing public tunnels were converted for cable use, and a third was built as a private venture. In 1906, all Chicago cable lines were converted to electricity and the tunnels were closed. All would reopen for streetcar service, but with the change to electricity streetcars could cross bridges and the tunnels were less important. One ended regular service in 1924, one was closed in 1939, and one remained in regular service until 1952. In 2010 all approaches had been covered but two tunnels still existed. These tunnels should not be confused with a network of small freight tunnels under the downtown area. History Background In 1882, the Chicago City Railway opened the first of two cable car lines south from the downtown business district. Used as the backbone of a system of local horse and electric lines, the cable lines were immediately successful and greatly improved public transit in the South Side. But the Chicago River, with its two branches, separated the North and West Sides from the downtown and South Side. To enter downtown cable cars would have to cross the river. The Chicago River was the city's port, and shipping had priority over land transport. Heavy river traffic and flat terrain required movable bridges, causing long traffic delays, and which could not have cables on them. But the city had previously built two horse and pedestrian tunnels under the river, both were in poor condition and neither was being used. One under LaSalle St. connected the North Side and one under Washington St. the West Side. A third tunnel next to Van Buren St., also connecting the West Side, was built later. Cable service An 1886 ordinance allowed the North Chicago Street Railroad to use the LaSalle St. tunnel in exchange for payment, moving a bridge, rehabilitating, and maintaining the tunnel. Cable service began on March 26, 1888 and ended