NS has two major routes entering Chicago from the east, a minor one from the south plus trackage rights routes from Decatur and Peoria.
Chicago Line (Dearborn Division)
The lion's share of the NS Chicago Line is composed of the former New York Central line connecting Buffalo, Cleveland, Toledo, and Chicago. However, at Whiting, Indiana, the line swings onto the one-time Pennsylvania main line that connected Pittsburgh, Ft. Wayne, and Chicago for the remainder of the journey finto Chicago. Both of these lines were operated by Penn Central and later Conrail, and both are part of the NS Dearborn Division.
The Chicago Terminal dispatcher handles all traffic between 21st Street Junction on Chicago's south side to Porter Junction at CP 482. Within this area, there are important interlockings at Rock Island Junction (CP 509), Indiana Harbor (CP 502) and Pine Junction (CP 498). This is one of the busiest main lines in the area with as many as 70 trains on an average day. In addition to NS freights, Chicago Terminal handles Amtrak trains to Michigan and to the east coast, as well as CSX and Canadian Pacific trains on trackage rights.
To add to the congestion, Indiana Harbor Belt uses trackage rights between Burns Harbor (CP 485) and Indiana Harbor. CSX eastbound trains leave the line at Porter and head north on the Grand Rapids Sub, as does Amtrak's Pere Marquette. Amtrak's other Michigan trains also leave at Porter using Amtrak-owned ex-Michigan Central tracks to Kalamazoo and Detroit, Michigan. Most CP trains continue east from Porter to Butler, Indiana, where they access NS's ex-Wabash line to Detroit. No commuter trains use the Chicago Line.
Most westbound NS freights leave the Chicago Line at CP 518, a couple of miles south of 21st Street, and head west to Ashland Avenue Yard. From there, other railroads may be accessed using former Chicago River & Indiana trackage previously owned by Conrail (and originally part of the New York Central family). This route, which traverses Brighton Park Crossing, is also part of the Dearborn Division. UP and BNSF trains can often be seen here.
Chicago District (Lake Division)
The Chicago District (NS prefers 'district' to 'subdivision') is a former Nickel Plate main line to Cleveland and Buffalo, and extends from Van Loon on the west side of Gary, Indiana, through Wayne/Spriggsboro to Fort Wayne. Before the Conrail merger, the Chicago District extended into Chicago, but west of Van Loon the line is now part of the Dearborn Division. About 25 freights a day use the Chicago District; many of them originate or terminate at Calumet Yard on the far south side of Chicago. Most steel mill traffic transfers to the Canadian National's former EJ&E main at Van Loon or to the Indiana Harbor Belt at Osborn. Intermodal trains use Landers Yard on Chicago's southwest side. No Amtrak or commuter trains use the route.
Kankakee Line (Dearborn Division)
This is former New York Central trackage extending east from Hennepin, Illinois, through Streator and Kankakee to Schneider, Indiana. It then heads north to a point near the Little Calumet River in Hammond, Indiana. Although NS operation ends there, the tracks continue north through Osborn, Gibson, Grasselli and Calumet to the lakefront industrial area of Indiana Harbor at CP 502. This segment is operated by the Indiana Harbor Belt under a long-term lease agreement. At Osborn, NS trains can transfer to the Chicago District or head north on IHB to CSX's Porter Branch at Gibson or continue still further to the Chicago Line at CP 502. Traffic is light, perhaps eight to ten trains daily, including a few BNSF freights that transfer at Streator and use it as a Chicago bypass to reach NS's yard at Elkhart. No Amtrak or commuter trains use this line.
Bloomington District (Illinois Division)
This line carries traffic between downstate Decatur, Bloomington, and Peoria, Illinois. It consists of the former NKP from Peoria to Gibson City, Illinois, and the former Wabash from Decatur to Gibson City where the two lines join with CN's former Illinois Central main line from downstate Gilman to Springfield and St. Louis. (Once used by IC's Green Diamond passenger trains, the former IC line is mostly abandoned south of Springfield.)
Though the NS Bloomington District doesn't enter the Chicago area, it is pertinent because NS has trackage rights on CN's former Illinois Central Gilman Line from Gibson City to Gilman, Illinois, as well as the its ex-IC Chicago Sub. Once in the Chicago area, they leave CN at 95th Street and head east to Calumet Yard. This trackage rights agreement allows NS traffic from Decatur or Peoria, Illinois to move to Chicago. At its peak, the CN Gilman and Chicago subdivisions saw between four and six daily NS trains.
More recently, NS has found it expedient to avoid using the trackage rights in CN in favor of an all-NS route via former Wabash rails to that railroad's namesake city in Indiana, and thence via the NS Marion District (ex-NYC) to Elkhart.
The Chicago Line does not have a major classification yard in the Chicago area. At NS's huge terminal in Elkhart, Indiana, trains are sorted and pre-blocked for Chicago delivery. From there, many trains travel directly to the yards of other roads in the Chicago area, with some transferring to the Indiana Harbor Belt at CP 502. Others proceed to Ashland Avenue yard, as noted earlier. The only major classification yard in the Chicago area is the NKP Chicago District's Calumet Yard. The primary intermodal facilities are Landers Yard on the ex-Wabash line (now Metra's Southwest sub), and the 47th Street and 63rd Street terminals along the Chicago Line. Most autorack traffic heads to IHB's Gibson Yard.
Nearly all NS dispatching is now located in Atlanta, Georgia.