When Amtrak took over intercity service on May 1, 1971, the 600-series trains continued to be operated by Penn Central, though they were listed in Amtrak schedules. The city of Philadelphia and the state both preferred to have Penn Central rather than Amtrak operate the service, as Amtrak was exempt from state control. On June 21, the ICC ruled that the service was not intercity rail, as sought by the state and not by Penn Central. On August 3, Fullam ordered Penn Central to continue operating the regional services.