No injuries were reported in derailments of Canadian National and SEPTA commuter trains.
The CN derailment occurred at 7:30 a.m. in Warren, Michigan, a suburban of Detroit and involved 12 cars leaving the rails.
The derailment snarled traffic during the morning rush hour.
News reports indicated that three of the derailed cars were tank cars carrying liquid chlorine and unrefined alcohol but they remained upright.
One of the cars was reporting to be leaking slightly but emergency officials said this did not pose a public hazard.
The train had 151 cars. Officials said the cleanup could last several days and traffic will continue to be disrupted.
Bus service on two routes was disrupted after a Southeastern Pennsylvania Transportation Authority train derailed late Wednesday morning as the train left the Trenton (New Jersey) Transportation Center.
The second and third cars of the four-car train bound for Philadelphia left the rails.
The train had 25 passengers aboard. New Jersey Transit Northeast Corridor trains to Trenton were also affected by the derailment and were experiencing delays of up to an hour.
SEPTA suspended service between Philadelphia and Trenton while the train was re-railed and removed.
Five trains were cancelled and service issues continued into Thursday morning with trains cancelled in each direction. Other trains were delayed up to 10 minutes.