Alton Junction in Chicago had its beginnings well before the start of the 20th century. It was constructed by a joint venture among five different railroads – the Chicago & Western Indiana (C&WI), Chicago & Alton (C&A), Chicago, Madison & Northern (CM&N), Pittsburgh, Fort Wayne & Chicago (PFW&C) and the Atchison, Topeka & Santa Fe (AT&SF). The C&A and CM&N were later acquired by the Illinois Central Railroad. The PFW&C eventually became the Pennsylvania Railroad.
Source: Industrial History: The Tower for the 21st Street Crossing Used to be Elevated
In the 1940s, 10 different railroads met at the Alton Junction at 21st and Canal Streets, just a few short miles southwest of downtown Chicago. The 10 railroads were the Illinois Central, Chicago & Alton, Atchison Topeka & Santa Fe, Pennsylvania, Chicago & Western Indiana, Chicago & Eastern Illinois, Erie, Wabash, Monon and Grand Trunk Western.
Source: https://railfanguides.us/il/chicago/interlocking/CHICAGOalton_jct.gif
The Alton Junction, more commonly known as the 21st Street Crossing, at one time had 26 diamonds to control over 150 trains daily through the junction. Alton Junction was controlled by a manned interlocking tower until 2005 when Amtrak transferred control to its new Chicago Terminal control center. At the north end of Alton junction is a huge vertical lift bridge that spans the South Branch of the Chicago River.
Source: Industrial History: 21st Street Crossing or Alton Junction
Running from south to north across Alton Junction was the double mainline of the Pennsylvania Railroad. Just to the west of the PRR double mainline was the 4-track Chicago & Western Indiana mainline, running from south to north and turning east over the PRR tracks just before the PRR vertical lift bridge. The Illinois Central and Santa Fe tracks ran from west to east crossing the PRR and C&WI tracks at Alton Junction. The Chicago & Alton also ran a double track mainline parallel to the Illinois Central and Santa Fe tracks, running from west to east before turning north onto the PRR tracks right before the PRR vertical lift bridge.
The destination of the Pennsyvania and Chicago & Alton passenger trains was Union Station. The Illinois Central passenger trains were headed to Central Station. The six railroads running on the 4-track C&WI mainline and the Santa Fe passenger trains were headed to Dearborn Station.
The double mainline PRR tracks ran south to north across the PRR vertical lift bridge into Union Station. The C&A passenger trains also used Union Station. In those days, the C&WI route was a four-track main line that paralleled the PRR on the west, running from the south to north. At the junction, the C&WI tracks crossed the IC and then curved northeast and crossed the PRR double mainline carrying passenger trains on their way to Dearborn Station. Passenger trains of the Wabash, Erie, Grand Trunk, Chicago & Eastern Illinois and Monon — as well as C&WI’s own commuter trains — used these tracks.
Source: https://monon.org/bygone_site/chicago/09-19-21stInterlocker-Chicago.jpg
In addition to scheduled passenger trains, Alton Junction also saw numerous C&WI transfer movements from Dearborn Station to the coach yards south of the crossing where Erie, Monon, C&EI, GTW and Wabash equipment was serviced. In addition, mail and express trains, as well as freight trains on the PRR, IC and C&A took place across the junction in very large numbers. The interlocking, required to be manually operated, resulted in Alton Junction being the largest and most active of all the Chicago rail junctions.
Most of this interlocking is gone now. Only 4 of the 26 diamonds still remain. Northeast of the existing diamonds, there is now a park instead of the four-track C&WI main. The ATSF tracks and passenger train facilities disappeared in the 1970’s, and the C&A tracks east of the junction have been torn up as well. The Chicago Transit Authority (CTA) now runs an elevated commuter train line from Midway Airport parallel to the old IC and Santa Fe tracks across Alton Junction above the old PRR double track mainline before turning east at 18th Street.
Source: Google Images
The former Pennsylvania Railroad mainline, running north-south, is now owned and operated by Amtrak as the southern gateway to the Union Station complex. The Norfolk Southern’s Chicago Line and the former BNSF Southern Transcon terminate at the southern entrance to the interlocking, but both NS and BNSF trains have trackage rights over the lift bridge to access the BNSF east–west main line. All of Amtrak’s east coast bound and Michigan trains use this track. The east–west line now belongs to the Canadian National Railway. It at one time was owned by Illinois Central and was the carrier’s route out of its Central Station to Iowa.
