Amtrak Hiawatha is the shortest freestanding corridor on Amtrak at only 86 miles long. Trains make 7 round-trips per day (6 times on Sundays) between Chicago and Milwaukee. The service is unreserved. Starting October 15, 2016, the line went to pricing Peak trains (the two morning trains to Chicago, and two evening peak trains from Chicago) more expensive than off-peak trains, previously all trains cost the same. In Chicago priority boarding is also provided through by passengers lining up near the tracks instead of in the north boarding lounge for passengers holding monthly and ten-trip tickets. As of 2019, Passengers boarding the two northbound peak period evening trains with monthly 10 trip tickets may use the Hiawatha Lounge, housed in the area of the former Metropolitan Lounge.
Trains consist of 6 Horizon Service cars (with possible Amfleet I subsitutes) running in push-pull mode with a ex-F40 Cabbage Car at one end (usually Chicago-bound) and the usual P42 Locomotive at the other end. The fact trains have the Cabbage car means that all trains accept checked luggage and starting in May 2016 unboxed bicycles between only the end point stops of Chicago and Milwaukee only. The train is entirely coaches with one coach a Quiet Car. There is no food service on any trains since at seat cart service was discontinued at the end of June 2013. This food service amenity was only provided on select afternoon and evening trains during weekdays and was discontinued to save money. The estimated $233,000 a year previously used to subsidize the cart service has been committed to giving the Hiawatha Service train sets wifi. The line is subsidized by the DOTs of both Wisconsin and Illinois, with Illinois providing 25 percent of the funding and Wisconsin the rest.
Amtrak Hiawatha Service trains are not the shortest distance individual trains Amtrak operates. This award for a route goes to the New Haven — Springfield Shuttles, these only run 62 miles but directly connect in New Haven to Northeast Regional Trains continuing south to Washington and points in Virginia.
There are a number of Commuter Rail Lines that are longer than the Hiawatha. In Chicago, The South Shore Line from Chicago to South Bend, Indiana is 90 miles long, longer than the Hiawatha (with fares, costing half as much as the Hiawatha but the ride taking nearly double the time, in much less comfortable conditions), although the more direct route used by Amtrak's Capitol Limited and Lake Shore Limited's from Chicago to South Bend is 2 miles lessw. Metra's longest line, the UP Northwest Line is 70 miles long.
In other cities some non-Amtrak operated Regional Rail Lines are longer than the Hiawatha Service route: