KARRS (Koiwai Area Regional Rail System) is a regional rail system comprising two lines in the Koiwai-Randgriz Metropolitan Area. KARRS is administered by the Koiwai Department of Transportation (K.), and is operated under contract by Ivalice National Railways. KARRS operates on weekends to alleviate metropolitan trafic. Service is suspended or reduced on select holidays. With some equipment capable of reaching speeds of 130 mph, KARRS is considered the fastest commuter railroad in Ivalice.
Trains are named based on major stations on the routes; these localities are Setsuna, Forriedor, and Randgriz City, Gallia. KARRS also provides local rail service within Koiwai with a reduced fare.