Ok, there are beltway railroads in Chicagoland.
But it seems the NYC, PRR and B&O had a few routes which went around the Windy City to the south.
I am surprised none gain any traction as an interchange bypass.
The one which surprises me is the Central's line which connected with the ATSF. In the diesel era, run throughs with this would be a natural.
I worked for the NYC in various marketing and operating department jobs between 1959 and 1967. There was some delay caused by switching in Chicago for western connections in 1959 but very little by 1969. From the time that the new Elkhart Yard was finished in 1958, most western traffic was blocked there. In 1967, there were blocks for MILW, C&NW, SOO-CGW, IC-west, CB&Q, RI, SF, WAB, and IC. All of those blocks departed Elkhart between 2:00A and 12:01P and all were delivered to connections the same day.
Streator-SF was one of our most important connections, with a through train from Boston to Streator. LS-3 left Boston at 7:15P, was classified at Elkhart 24 hours later and arrived Streator at 9:30A, 39 hours after leaving Boston. Connecting from New York on LS-1 was a Streator-SF block made at 72nd St and departing New York at 12:50A for a 34 hour trip to Streator.
Run-through of power was a secondary consideration. To us, run-through meant large blocks of cars from Elkhart or Indianapolis to Kansas City, Galesburg, Silvis, Pine Bluff or Little Rock. Interchanges of trains required crew changes. If power ran through, then you had to deadhead the crew back to the engine house, so it cost a lot of money to run the power through.