Officials investigating a train collision in Connecticut have ruled out foul play and are studying a rail fracture where a derailed commuter train was struck by another bound for New York City.Service on Amtrak, which uses the same rails, remains suspended service through Sunday between New York and New Haven. There is limited service between Boston and New Haven according to the railroad. Service is also affected on some Metro-North lines.

National Transportation Safety Board member Earl Weener says the broken rail is of substantial interest to investigators and a portion of the track will be sent to a lab for analysis.

Weener says it's not clear if the accident caused the fracture or if the rail was broken before the crash. He says he won't speculate on the cause of the derailment.

Gov. Dannel P. Malloy couldn't say when Metro-North Railroad service would be restored. The crash also caused Amtrak to suspend service between New York and Boston.

National Transportation Safety Board investigators arrived Saturday and are expected to be on site for seven to 10 days.

The Associated Press contributed to this story.