Cities - Chicago - Peoria - Rockford - Springfield - Princeton - Champaign-Urbana
See Chicago 'L' for CTA route relations.
See Metra for Metra route relations.
Listing at the Metra website.
More information can also be found at the Chicago Rail Fan website.
Chicago Airport Authority
There is an Airport Transit System as a VAL (Véhicule Automatique Léger) that should be entered here.