Listed are dates of use for the consolidated routings, and key interlockings involved.
On 3/6/72, nearly a year after Amtrak's formation, full consolidation into Union Station was finally achieved. Although this is Amtrak's most awkward routing in the Chicago area. Trains would back south out of Union Station and turn west on the BNSF former Burlington main line to Union Street. Trains would then proceed forward, east over the St. Charles Air Line bridge, and join former Illinois Central trackage at 16th Street. Finally at South Wye Jct., a former interlocking a short distance south of the former Central Station location, trains would turn south and join the original main line. Amtrak trains south to Carbondale and New Orleans use this routing. And until 10/16/73, Amtrak's James Whitcomb Riley (now the Cardinal) also used this route. Proposals have existed to create a more direct routing, possibly involving the former Nickel Plate right of way in the Grand Crossing area, but nothing has progressed forward. An alternate routing sometimes used involved backing out of Union Station to south of 21st Street on the former Pennsylvania Railroad line, and proceeding forward northeast on a connecting track with the former Illinois Central line.
Illinois Central (Iowa Division)
IN USE: 2/14/74-10/1/81
KEY INTERLOCKING: Bridgeport
From 2/14/74 until 10/1/81, Amtrak's Black Hawk operated between Chicago and Dubuque. By then Illinois Central and Gulf Mobile & Ohio had merged, forming the Illinois Central Gulf Railroad. Both former railroads and Santa Fe Railway shared a 2 track bridge at Bridgeport. So the Black Hawk could use the Gulf Mobile & Ohio formerly Alton route between Union Station and Bridgeport.
With the formation of Amtrak, the two Santa Fe trains retained were immediately moved to Union Station. These trains were the Super Chief and the Texas Chief. Santa Fe, Gulf Mobile & Ohio, and Illinois Central shared a 2 track bridge at Bridgeport. So the Santa Fe trains could use the Gulf Mobile & Ohio formerly Alton route between Union Station and Bridgeport. The Texas Chief, later renamed the Lone Star, was discontinued 10/1/79. And the Super Chief, now named the Southwest Chief, was transferred 8/1/96 to the former Burlington routing between Chicago and Galesburg.
Chicago & Western Indiana
IN USE: 8/1/74-present
KEY INTERLOCKINGS: 21st Street, 40th Street (deactivated)
Except for Santa Fe, all railroads using Dearborn Station operated over the jointly owned Chicago & Western Indiana Railroad. All passenger trains using this trackage were discontinued with the formation of Amtrak. Norfolk & Western, formerly the Wabash Railroad, continued to operate a daily commuter train between Chicago and Orland Park. A new track and platform was constructed along the west side of Dearborn Station, enabling the main station to be closed. The bankruptcy of the Penn Central Railroad resulted in deteriorated track conditions for several lines in Indiana used by Amtrak. And on 8/1/74 it became necessary for Amtrak to use railroads which had formerly served Dearborn Station. The James Whitcomb Riley (now the Cardinal) began using Chesapeake & Ohio between Chicago and Cincinnati. The Floridian began using former Chicago & Eastern Illinois trackage between Chicago and Evansville. Although on 9/14/75 the Floridian was moved to former Monon trackage between Chicago and Louisville. At 40th Street in Chicago, a backup move was required between the Chicago & Western Indiana trackage and paralleling former Pennsylvania Railroad trackage, for access in and out of Union Station. On 12/2/76, the Orland Park commuter train was moved to Union Station, using a newly constructed connection at 21st Street. This connection had been completed a few weeks earlier, eliminating the backup move at 40th Street for the Amtrak trains. The commuter service was expanded over the years into the present Metra Southwest Service. The James Whitcomb Riley was moved off the Chicago & Western Indiana on 6/12/77, using a route involving the Baltimore & Ohio east of Chicago. And the Floridian was discontinued 10/1/79. Amtrak returned to the former Monon route on 10/1/80 with the introduction of the Hoosier State, between Chicago and Indianapolis. But that train used a former Pennsylvania Railroad routing between Chicago and Munster IN, with a new connecting track constructed at Air Line interlocking. On 4/27/86, the Cardinal (formerly the James Whitcomb Riley) joined the Hoosier State over the former Monon. And the Cardinal subsequently largely replaced the Hoosier State. On 6/30/93, these trains returned to the former Chicago & Western Indiana between Chicago and Dolton. Continuing via the former Chicago & Eastern Illinois and Grand Trunk Western via Thornton Jct. to GT Crossing in Munster, with connecting tracks at those interlockings. This is the one remaining Amtrak train using the former Chicago & Western Indiana, although sometimes Amtrak trains between Chicago and St. Louis may detour via the former Chicago & Eastern Illinois.
In 1968, the Penn Central merger resulted in construction of a new connection in Whiting IN, enabling former New York Central trains to use former Pennsylvania Railroad trackage in and out of Union Station. In 1979 the former Pennsylvania Railroad trackage between Whiting and Indiana Harbor was abandoned, the interlocking at Whiting was deactivated and former Pennsylvania Railroad trains were consolidated onto the former New York Central line east of Whiting. The interlockings in the Indiana Harbor area were reconfigured to accommodate this consolidation.
Rock Island
Rock Island did not join Amtrak, and continued to operate passenger trains independently until 12/31/78, remaining at La Salle Street Station. Around 1971 construction was actually started on a connecting track at the southwest quadrant of the Englewood interlocking, which would have enabled Rock Island trains to access Union Station via the former Pennsylvania Railroad. But the track was never completed.
All passenger trains were initially discontinued with the formation of Amtrak. On 4/1/76 Conrail acquired Penn Central and other railroads, including Erie Lackawanna. And Conrail abandoned lines with little traffic potential, including the Erie Lackawanna main line through Indiana. Chesapeake & Ohio had trackage rights over a segment of the Erie Lackawanna line through Hammond, and the James Whitcomb Riley had operated over this segment. Chesapeake & Ohio began rerouting freight trains via the Baltimore & Ohio main line east to Wellsboro IN, and via a Chesapeake & Ohio branch line which joined the Cincinnati main line at La Crosse IN. Amtrak continued to operate through Hammond, but with complications, as Chesapeake & Ohio did not want to assume responsibility of the former Erie Lackawanna line. And on 6/12/77, the James Whitcomb Riley began using the freight routing via the Baltimore & Ohio. A backup move was required at Pine Jct., (NE Tower on former New York Central), connecting with Baltimore & Ohio trackage. This connecting track had existed to enable Chesapeake & Ohio former Pere Marquette trains to switch to and from New York Central, over which Chesapeake & Ohio had trackage rights east to Porter. Around 1979, consolidation of trackage between Gary and Indiana Harbor eliminated the backup move. On 4/27/86 the Cardinal (former James Whitcomb Riley) was moved to former Monon trackage south of Chicago, to enable downgrading of the former Chesapeake & Ohio line. Amtrak returned to the former Baltimore & Ohio on 11/11/90, when the Broadway Limited was moved off the former Pennsylvania Railroad line through Fort Wayne to enable downgrading of that trackage. Service was discontinued 3/7/2005.
Chesapeake & Ohio (Pere Marquette)
IN USE: 8/5/84-present
KEY INTERLOCKING: Pine Jct./NE Tower (deactivated)
After initially not being included in the Amtrak system, on 8/5/84 service was introduced between Chicago and Grand Rapids. Because the former Pere Marquette had trackage rights over former New York Central between Pine Jct. and Porter, simple track connections were already in place for the service.
Soo Line (Wisconsin Central)
IN USE: 8/19/96-present
KEY INTERLOCKING: Tower B-12/Franklin Park
Never participated in Amtrak service. But on 8/19/96 Metra introduced its North Central commuter service over this line. This line basically crosses the Milwaukee West line at Tower B-12 at Franklin Park, where new connecting tracks were constructed at the northeast quadrant.
None of the Chicago & North Western trains were retained by Amtrak, although Amtrak trains will occasionally detour over their trackage. For the old Galena Division west, trains can switch to and from Chicago Union Station trackage at Tower A-2. Detours over the old Wisconsin Division north are more rare, as the more normal detour route for Amtrak's Empire Builder would be via the former Burlington Route through Aurora and Savanna. When floods have made both the former Milwaukee Road and Burlington Route impassible, the Empire Builder has been known to detour via Chicago & North Western. Trains would use the Milwaukee West line between Union Station and Tower B-17 at Bensenville, the freight connections north of Bensenville Yard connecting with trackage rights over the Chicago & North Western freight line to Milwaukee, and beyond to the Twin Cities.