Iowa Interstate ends at Blue Island here in Chicago. It interchanges with EJ&E just east of Joliet. Why do they haul cars to Blue Island and bring them back to the EJ&E in a separate move instead of just leaving them on the interchange track when heading east? This is a 20-25 mile backhaul. Today Iowa Interstate used two GP 38s to haul about fifteen steel coil cars and a gondola to the EJ&E from Blue Island. That takes a crew probably two hours or more and a lot of fuel.
The EJ&E interchange is located where IAIS has trackage rights over Metra's Rock Island District. There is only a one-hour window between suburban runs so it may not be feasible to drop the interchange on the eastbound run without delaying a suburban train.