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

Car computers keep a record of the activities of all surrounding cars so they can quickly discard information about a car moving quickly in the opposite direction but track a car moving in the same direction around a corner and determine if it will soon be in the same lane as your own.

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It explained that this was "because the previous train, an engineers' on-track machine, had passed through the crossing in the opposite direction to normal".

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Red Bull look tremendous through the first two sectors but struggle in the third, Brawn GP pretty much the opposite, Ferrari - and Felipe Massa in particular - effectively 'own' this track, McLaren continue to throw in the odd glimpse of decent pace and, on top of all that, Williams pair Nico Rosberg and Kazuki Nakajmia sit third and fourth right now.

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