Amtrak says the heat wave was to blame for overhead wire problems that disrupted rail service along the Northeast Corridor in New Jersey.
The power lines were sagging and that caused delays for Amtrak passengers and New Jersey Transit commuters between Metropark and Trenton Wednesday afternoon.
Amtrak spokesman Cliff Cole says the hot temperatures caused the tension on the power lines to loosen.
Workers completed repairs by 10:20 p.m.
Cole says officials will monitor the overhead lines throughout the heat wave.
Temperatures in New Jersey have been in the 90s all week.