Turboliners arrived on the Detroit run on April 10, 1975. Additional equipment allowed Amtrak to add a round-trip in late April; the arrival of a third trainset in May made Chicago–Detroit the "first all-turbine-powered route". After one year of operation, ridership on the corridor had increased by 72 percent. The fixed capacity of 292 passengers on an RTL trainset proved an impediment; Amtrak could not add capacity when demand outstripped supply. Amtrak replaced one of the trainsets with a conventional locomotive hauling then-new Amfleet coaches in 1976; Turboliner service ended altogether by 1981 as more Amfleet equipment became available.