Story highlights NTSB officials should be on site by 9 a.m. Saturday, spokesman says

One train derailed then hit a train going the other way, spokeswoman says

Two hospitals have treated 67 injured people, spokespeople say; 2 are critical

A mayor says it may take weeks to get train service moving again on that key corridor

Two Metro-North passenger trains heading in opposite directions collided during rush hour Friday evening in southwestern Connecticut, damaging both trains and leaving dozens injured -- some of them critically -- authorities said.

A train heading from New Haven to New York City derailed around 6:10 p.m., hitting the other train in Bridgeport, Connecticut, Metro-North spokeswoman Marjorie Anders said. That caused some cars on the second train, which was destined for New Haven, to likewise leave the tracks.

Gov. Dannel Malloy told reporters Friday night that five people were "critically injured," one of whom was in "very critical condition."

Two of the 26 people being treated at Bridgeport Hospital are in critical condition, said spokesman John Cappiello.

St. Vincent's Medical Center, also in Bridgeport, treated 41 patients from the incident, hospital spokeswoman Lucinda Ames said. One of those was in serious condition and in intensive care, while the others mostly had minor injuries like "you might get in a car accident."

Photos: Trains collide in Connecticut Photos: Trains collide in Connecticut Trains collide in Connecticut – A Connecticut state investigator examines the scene of a Metro-North train collision on Saturday, May 18, in Fairfield, Connecticut. Two commuter trains collided during rush hour on Friday, sending dozens to the hospitals and shutting down a busy section of track, which is expected to affect commuters for weeks to come. Hide Caption 1 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Construction equipment is moved in to place. The wreckage will not be removed until investigators finish examining the site, which may be Sunday. Hide Caption 2 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – National Transportation Safety Board investigators examine the scene of the collision. Hide Caption 3 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Investigators walk past two train cars damaged in the collision on Friday, May 17. Hide Caption 4 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Onlookers gather at the scene on Friday, May 17. Hide Caption 5 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – People are seen inside one of the two derailed trains on May 17. Hide Caption 6 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Debris and twisted metal is seen inside one of the derailed trains on May 17. Hide Caption 7 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Both trains were damaged and dozens were injured, though officials say the injuries aren't believed to be life-threatening. Hide Caption 8 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Onlookers gather as police cordon off the area. Hide Caption 9 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – A woman injured in the crash is prepared to be transported to the hospital. Hide Caption 10 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Amtrak also announced early Friday night that it had suspended all travel between New York and Boston indefinitely after the crash. Hide Caption 11 of 12 Photos: Trains collide in Connecticut Trains collide in Connecticut – Passengers gather as they wait for a bus to pick them up from the scene of the collision. Hide Caption 12 of 12

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By 9:45 p.m., 11 of the 67 who had gone to hospitals had been released.

A passenger in a middle car of the New York-bound train, Chris Martin, recalled to CNN how his car went dark after the crash, then someone over the intercom "called all the doctors up front."

He and others aboard his "pretty full train" were evacuated, most of them physically fine if emotionally shaken. But there were signs of injuries outside, as Martin said he personally saw eight or nine ambulances and a number of wounded people on stretchers.

Brian Alvarez, who saw the wreckage, described the scene as "pretty graphic."

"I saw this one car and it was completely destroyed, and they were pulling people out of the car," Alvarez said. "... They were all bloody."

Power was shut off along the line and service has been halted -- westbound past Bridgeport, which is about 60 miles northeast of New York City on the Long Island Sound, and eastbound beyond South Norwalk -- because of the derailment.

Amtrak also announced early Friday night that it had suspended all travel between New York and Boston indefinitely after the crash.

Bridgeport Mayor Bill Finch said such travel headaches could persist for weeks, because the two tracks affected by the derailment -- which are both "shot right now" -- may take weeks to repair. Because of a bridge replacement project, those two tracks are the only way in and out of New York City by train from that part of Connecticut.

Workers will need to not only remove disabled trains, but also remove the tracks, regrade the rail bed, then lay down the tracks again, according to Finch.

"This is our pipeline to New York City, and it's going to be shut down for some time," the mayor said. "And it's going to cost this region a great deal of money, frankly, not just to repair it but the lost wages and the lost economy."

Officials from the National Transportation Safety Board will head the investigation into the crash. Terry Williams, a Washington-based spokesman for that agency, said a team should be on site by 9 a.m. Saturday.

"We have no reason to believe that it's anything but an accident," Gov. Malloy said.