Soo trains en route to and from the Southeastern used the following different routes. At Franklin Park they entered IHB trackage. The IHB was followed across most of it's main line to the east end of Gibson Yard where they turned south entering the IHB's portion of the Kankakee Line. Ownership of the Kankakee Line changes at Osborn Tower to Conrail. The Conrail Kankakee Line is followed to Schneider, IN where the Danville Secondary is reached. Actually the Danville Secondary is simply the southward (compass) extension of the Kankakee Line. At one time this route extended all the way to to bottom of Illinois. It is former New York Central.
The Danville Secondary is followed through Indiana to Terre Haute where it crosses and connects with the Conrail St Louis Line. I may be incorrect about this as I don't have my timetables handy. I also cannot recall the exact name of this connection right now. Maybe it will come to me. If not I'm certain somebody will remember it. Originally the connection here was backwards. Milwaukee trains had to enter heading timetable west pulling the train clear of the connection and into a small yard there, then run around the train and pull it east to Preston where it connected to the Latta Sub and then proceed onto the Milwaukee/Soo. A new connection was built to allow forward access with a wye in the northeast quadrant.
This routing was the initial route the Milwaukee and later the Soo began using in April 1980 when they retrenched from and abandoned or sold off some two-thirds of their railroad as aprt of the bankruptcy reorganization. The Conrail route was used until 1990. Conrail had let the Danville Secondary track conditions deteriorate badly. They operated no regular through service on the line only locals and the as required grain trains. Soo/Milwaukee operated the only regular through trains on the line. The Soo wanted to purchase the Danville Secondary from Conrail and undertook negotiations for such. However, Conrail wanted to bundle several other lines with the Danville and was trying to force the Soo to purchase it as a package. The other trackage included the old Peoria & Eastern all the way to the namesake city as well as the Olin Secondary. Soo wasn't interested in any of this other trackage and declined. I was told several years later by a Soo manager he thought they made a big mistake in passing up on the package. The P&E line would have given them opportunities for new business, creating a new gateway as well as growing existing business. He also felt they could have conceivably leased out the Olin to a short line operator if they didn't want to operate it themselves.
With badly deteriorated track on the Danville Secondary, including some 70 miles 10 MPH speed restrictions, it was taking the Soo two or three crews to get the trains from Bensenville to Latta Yard. For a time their operating plan had a crew out of Bensenville taking the train to Gibson on the IHB where a Latta crew took over and took the train south from there. Eventually it became a run as far as you can go from Bensenville then get recrewed plan. Southeastern trains did work en route. 204 later resymbolled 240, did work at Gibson picking up loading for points on the Latta Sub. They also did work at Kentland, IN performing interchange with the Toledo, Peoria & Western at that location. Fed up with the excessive delays to their trains and Conrail's resistance to fix up the Danville Sub, Soo went to the FRA and demanded action. The Feds required Conrail to repair the track and they did. However, they didn't fix it all, just short stretches which still required slow running and multiple crews to operate the trains between Bensenville and Latta Yard.
The Soo was able to gain operating rights via CSX from Spring Hill where they crossed and connected with the former C&EI, now part of CSX. This line became Missouri Pacific in 1968 when the MoPac gained control of the C&EI. In 1969 MoPac spun this and all the Evansville Division trackage of the former C&EI to the Louisville and Nashville.This was a condition of their gaining control of the C&EI. Eventually the L&N and its relatives of the "Family Lines" were merged into the Seaboard System and six years later Seaboard became the S in CSX Transportation when parent CSX Corp merged all of their component roads of the Chessie System and Seaboard System into one railroad.
Initially these were detour movements but became regular trackage rights. Once the trackage rights agreement was worked out, Soo filed for and was granted abandonment of the trackage rights on the Danville Secondary. In 1995 Conrail removed the Danville Secondary from service but did not file to abandon it at that time.
Soo trains operated from Spring Hill, IN to Woodland Jct, IL on CSX. At Woodland Jct the Evansville Subdivision ended and joined the joint UP/CSX double track route from Woodland Jct to Dolton, IL. This portion of the former C&EI was technically owned and operated by Union Pacific, gaining ownership with their takeover of MoPac in December 1982. Both CSX and UP contributed to maintenance of the route using a complicated formula based on car counts and other factors. It is operated, maintained and dispatched by Union Pacific with their timetable and rulebook (General Code of Operating Rules) in effect and UP handles all local industry work. Some of this local business is actually CSX business but UP handles all the work billing CSX for it.
At Dolton, IL, the location of Dolton Jct (also in the past referred to as "the Panhandle") Soo trains use the connection there and enter IHB trackage. They follow the IHB from Dolton back up to Franklin Park and the connection back to the Soo where IHB trackage ends.
Now for a time in the mid 90's, IHB crews handled 201/204 between Bensenville and IHB's Blue Island Yard. Soo crews based out of Latta took the train from Blue Island to Latta via the UP/CSX routing. Soo transfer crews would bring 204 to Norpaul Yard in Franklin Park where an IHB crew would take over and bring the train to Blue Island. The train was reblocked here with cars for the IHB and connections coming off and cars for the Soo/Southeastern added. In my time at the IHB, I operated the 201/204 and later, 240/241 trains. After parent CP pulled most of their business out of Blue Island in favor of the BRC, 240/241 usually passed through Blue Island without recrewing. 241 would set out cars en route to Bensenville and 240 would pick up cars en route to Latta. Eventually these trains were routed off the IHB for the UP/CWI routing to/from Clearing Yard.
The Soo operated coal trains on the UP/CSX route as well. These trains were handled by Soo crews all the way through to the Belt Railway of Chicago's Clearing Yard via the IHB to 71st Street. They also brought the empties back out from the BRC taking them back to Latta. They also brought coal trains to the IHB for Inland Steel and others for forwarding to the South Shore. The loads carried symbols 781 and 783 en route to the BRC, empties were 780 and 782, and I believe 785 and 787 en route to the IHB and 784 and 786 for the empties. The coal trains en route to the BRC were rerouted and handled north of Dolton Jct via the UP's former Chicago & Western Indiana line in which CSX had operating rights. C&WI was jointly owned by MoPac (C&EI), L&N (Monon), GTW, N&W (Wabash) and Conrail (Erie-Lackawanna) . C&WI and BRC shared common management at one time. When the CWI was dissolved in the 1980's UP took a 99 year lease of the Dolton Branch of the CWI between Dolton Jct and 80th Street in Chicago where it connected to the BRC route from South Chicago towards Clearing Yard.
The Soo routing over CSX was not without it challenges. Surges in business in the 90's on both CSX and UP brought huge delays as there was lots of congestion on the route. Sometimes it took 2 or 3 crews to move the trains between the Latta Sub and Chicago on much better railroad. I can recall 204/241 sitting and waiting to depart for hours at Blue Island Yard because the UP had so much congestion they couldn't take the Soo train. The same situation occurred at Spring Hill trying to get onto CSX there for the trip north.
An interesting footnote: CP Rail is minority owner of the IHB. In those days when Conrail was still Conrail, they were the senior owner with 51% and CP through Soo and Soo's acquisition of the Milwaukee owned 49%. The IHB handled a huge volume of CP/Soo business at Blue Island until 1994. They tried squeezing the IHB into lowering their switching and forwarding charges. The IHB, operating semi-autonomous, set their own prices and refused. From what I was told their profit margin would have been greatly squeezed had they agreed to CP's demands. The BRC was willing to make a deal with CP so they moved their business there.