The Indiana Harbor Belt Railroad (IHB) is a Class III railroad in the Chicago. The line comprises 320 miles (510 km) of track—30 miles of single mainline track, 24 miles (39 km) of double-main track and 266 miles (428 km) of additional yard and side track—starting northwest of Chicago in Franklin Park, Illinois traveling southeast around the city to its headquarters in Hammond, Indiana.

The RRs largest yard, Blue Island, is located in Riverdale, Illinoiswith other yards in the Indiana cities of Hammond and East Chicago. The Gibson Yard, located in Hammond, is arguably the largest auto-switching operation in the United States.