CSX enters the Chicago area on two major routes and several minor ones.
Former Baltimore & Ohio Main Line
The former B&O main line is the busiest of CSX's lines in the Chicago area, with 40 to 50 trains daily. The B&O delivers all traffic from east coast points to Chicago.
From Pine Junction to the west, this route technically belongs to the Baltimore & Ohio Chicago Terminal Railroad, a former subsidiary of B&O. Even though the B&O itself is long gone, B&OCT still exists (on paper at least) and is now a CSX holding. No commuter or Amtrak trains use this route.
This route is divided into four subdivisions, but only the first three listed below are major arteries.
This subdivision extends from Garrett, Indiana (about 25 miles north of Ft.Wayne) west through Wellsboro to Willow Creek Junction, where it crosses CSX's Porter Branch (former Michigan Central main line, later a Conrail property). A connection was constructed after the Conrail breakup to allow westbound trains on the Garrett Sub to access the Porter Branch and is used by a small number of trains.
The Barr Subdivision runs between Willow Creek and Blue Island Crossing, passing through Miller, Pine Junction, Calumet, State Line, Calumet Park and Dolton. At Pine, the trackage becomes B&OCT property and remains so for the rest of its Chicago route. The Barr Sub of course also travels through Barr Yard, CSX's major classification yard in the Chicago area. A connection between Barr and Indiana Harbor Belt's nearby Blue Island Yard allows for extensive interchange between the two roads.
Blue Island Subdivision
This subdivision extends from Blue Island Crossing north through Chicago to Rockwell Street (also known as Ogden Junction), located near Roosevelt Road and Western Avenue. It passes through 75th Street (Forest Hill), where it connects with the Belt Railway, and continues north to Brighton Park, where it crosses Canadian National's Joliet Sub. It also connects with BNSF's Chicago Sub (the "racetrack") at about 18th Street. Rockwell Street should not be confused with Rockwell Junction, which is about a mile to the north and does not involve CSX.
This subdivision connects with the Blue Island Sub at Rockwell Street and runs due west to Forest Park where the tracks become the property of Canadian National (ex-Wisconsin Central, ex-Soo). The Altenheim Sub is out of service from Rockwell St. to the Belt Railway crossing near Cicero Avenue.
Former Chicago & Eastern Illinois Main Line
Nearly all CSX traffic from the south enters Chicago on this route. CSX inherited it from Louisville & Nashville who acquired it from C&EI. The line runs north from Evansville, Indiana, to Woodland Junction, where it joins Union Pacific's ex-C&EI, ex-Missouri Pacific line from St.Louis and the southwest. From Woodland north to Dolton, the line is jointly owned but is dispatched and maintained by UP as part of their Villa Grove Sub.
This line extends from Danville, Illinois, to Woodland Junction. CSX inherited L&N's ownership of this segment. Many CSX trains from the south leave UP tracks at Dolton Junction and join the Barr Sub for the short trip to Barr Yard. Other trains continue north to reach Clearing Yard or CSX's nearby Bedford Park intermodal terminal. Traffic averages around 15 to 20 trains per day; a few of them being Indiana Rail Road trains exercising haulage rights. No Amtrak trains use the Woodland Sub.
Other Routes Into Chicago
This line is made up of former Monon trackage extending from Greencastle, Indiana north through Lafayette to Maynard (Munster, Indiana). North of Maynard into Hammond, the Monon track is out of service. Hence, trains from Lafayette transfer to CN's ex-Grand Trunk Western main line (Elsdon Sub, now operated by CSX) and head northwest to Thornton Junction, where they access the UP's Villa Grove Sub.
From Thornton, they run north through Dolton. As with the Woodland trains, trains can reach either Barr Yard or Clearing. An average day sees about six trains. Trains from Indianapolis access the Monon at Crawfordsville, Indiana. Amtrak's Cardinal (and until its demise, the Hoosier State) uses the Monon Sub, making the same connections at Maynard and Thornton. At Crawfordsville, Indianapolis-bound trains transfer to CSX's ex-Conrail, ex-P&E route.
Grand Rapids Subdivision
This is a former Pere Marquette (later, Chesapeake & Ohio) route between Grand Rapids and Porter Junction. At Porter, CSX trains access Norfolk Southern's Chicago Line and proceed west on trackage rights to the Barr and Lake subs at Pine Juction. Amtrak's Pere Marquette between Chicago and Grand Rapids uses this route. About six to eight trains a day can be seen on the Grand Rapids Sub.
The Porter Branch runs west from Porter Junction to the Indiana Harbor Belt main at Ivanhoe on the far west side of Gary. Further west, at Calumet Park and also near Dolton, CSX trains access the Barr Sub. Other Class 1 roads use this line on trackage rights. Eastbounds feed into the Chicago Line at Porter and continue to NS's classification yard at Elkhart, Indiana. The Porter Branch was once part of the Michigan Central Chicago-Detroit main line (later New York Central), but the crossing with the Chicago Line at Porter was severed back in the 1970s. No commuter or Amtrak trains use the Porter Branch.
This line is known locally as the B&O passenger line, and at one time began at Pine Junction, leading off the Barr sub. However, it was cut back in the 1970s to a point about three miles to the northwest. As of 2019 few if any CSX trains use this subdivision. However, the South Chicago & Indiana Harbor (formerly Chicago Short Line) uses this route to serve steel mills in East Chicago. Back in the old days, B&O passenger trains were the primary traffic on the Lake.
New Rock Subdivision
This is a segment of the former Rock Island main line running between Joliet and Bureau, Illinois. East of Joliet, the line is owned and operated by Metra, and CSX trains use trackage rights to reach Barr Yard. West of Bureau, the track belongs to Iowa Interstate, who uses trackage rights on the New Rock and Metra to reach the Chicago area. CSX also operates a portion of a line running south from Bureau to Peoria and it is also part of the New Rock. Very little CSX traffic actually uses the sub; on most days just an out-and-back local freight. No Amtrak trains use the New Rock, and Metra's commuter trains terminate at Joliet. .
Chicago Heights Subdivision
This obscure line runs from Harvey Junction just west of Barr Yard south to end of track at the suburb of Thornton. At one time, it extended further through Chicago Heights to Faithorn, Illinois. South of Faithorn the track belonged to the Milwaukee Road who used trackage rights on B&OCT to reach there. The Milwaukee line ran south through Danville, Terre Haute and Bedford, Indiana. The Terre Haute-Bedford segment is now owned by the Indiana Rail Road. A segment from Danville north to Iroquois Junction is now owned by Kankakee, Beaverville & Southern. Everything else is gone.
Fort Wayne Line
CSX also owns a large segment of this former Pennsylvania main line, extending from Tolleston Junction in Gary, through Ft. Wayne to Crestline,Ohio. However, in 2004 CSX leased this route to Rail America (later acqiured by Genessee & Wyoming), and it is now operated as the Chicago, Ft.Wayne & Eastern Railroad. At Tolleston, the line feeds into the Porter Branch, and CF&E trains head west to Indiana Harbor Belt's main line at Ivanhoe. They tie up at IHB's Blue Island Yard.
This former Grand Trunk Western line extends from the south side of Chicago to Griffith, Indiana. This trackage belongs to Canadian National. However, in 2013 CSX was granted an easement on it by CN, and it is now controlled and operated by CSX from Chicago to Munster as if it were their own property. CSX also acquired trackage rights on the remaining segment between Munster and Griffith. For more on this subdivision, see the CN section of this page.
Located near Riverdale, Illinois, this yard is CSX's major Chicago-area classification yard. It is flat-switched and has been downsized as part of CSX's Precision Scheduled Railroading program. Some trains that once used Barr are now sent to BRC's Clearing Yard. CSX also has two intermodal terminals in the Chicago area: Bedford Park, located on the south edge of Clearing Yard, and 59th Street (a former Pennsy yard) on B&OCT's Blue Island sub. Autorack classification is done at IHB's Gibson Yard.
Until 2018, nearly all Chicago area dispatching was carried out at a facility in Calumet City, Illinois. However, now the dispatching is done from Jacksonville, Florida.