Federal experts determined earlier that a truck driver skidded nearly 300 feet before slamming into the side of the train in June 2011, killing him, a crew member and four passengers, including a woman from West Jordan, Utah.
NTSB's preliminary findings in September offered conflicting accounts of whether the guard crossing arm operated properly. But a time-lapse photo presented to the board in Washington on Tuesday showed the gate fully extended 4 seconds before the crash.
NTSB Chairman Deborah Hersman also said that it's clear the truck's brakes had not been maintained properly.
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