Then the second engineer noticed strange movement in the overhead catenary wires above the eastbound train, and hit the emergency brake on his train, Mr. Cahill said.

WSJ: Probe of Metro-North Derailment in Connecticut Focuses on Rail

In a statement issued Friday, the NTSB said the engineer of the eastbound train that derailed told investigators he noticed "an unusual condition on the track" as the train approached the area of the derailment in Bridgeport, Conn.

WSJ: Probe of Metro-North Derailment in Connecticut Focuses on Rail

The eastbound train, headed to New Haven from Grand Central Terminal, derailed at about 6:10 p.m. just east of the Fairfield Metro station, and hit a westbound train on the opposite track, Metro-North spokeswoman Marjorie Anders said, knocking several cars of that train off the rails.

WSJ: Train Derailment Injures Dozens

Using interviews, inspections of wreckage and reviews of maintenance data, NTSB investigators have determined that the first, eastbound Metro-North train derailed and came to a stop in the path of an approaching westbound train.

WSJ: Probe of Metro-North Derailment in Connecticut Focuses on Rail

As each eastbound train arrived at the front of the platform at Exchange Place last week, a PATH worker, Raishea Haines wrote down the number of the lead car.

WSJ: PATH's Road Back Is Rocky

One eastbound train derailed, coming to rest in the path of a westbound train that sideswiped it, damaging several cars and tearing up rails.

WSJ: Rail Corridor Hit With Major Outage

In the days ahead, our train will pass a succession of monstrous eastbound freight services, groaning with raw materials: Albertan oil and yellow sulphur, British Columbian coal and lumber, but mostly grain from the prairies.

BBC: The wonders of Canada by rail