A garbage truck involved in a fatal Amtrak accident late last month had entered a grade crossing after the warning gates were lowered, the National Transportation Safety Board (NTSB) announced yesterday.

On Jan. 31, an Amtrak train struck a garbage truck that was stopped at the crossing in Crozet, Virginia. The train was carrying Republican members of Congress on their way to a legislative retreat in West Virginia.

As a result of the crash, one truck passenger died; another truck passenger sustained serious injuries and the truck’s driver sustained minor injuries. Three Amtrak crew members and three train passengers sustained minor injuries, according to the NTSB’s preliminary summary of the accident.

The grade crossing is active and includes advance warning signs and pavement markings on its approach. The crossing also is equipped with crossbuck signs, warning lights, bells and gates.

Data from the train’s forward-facing camera inside the locomotive showed that as the crossing came into view, the gates were down and the garbage truck was on the grade crossing. Witnesses to the crash reported that the truck had entered the crossing after the gates were down.

During the crash, the front axle of the lead locomotive derailed as the train continued moving; however, the locomotive remained upright.

All aspects of the crash remain under investigation, NTSB officials said. Ultimately, the board will determine a probable cause and issue safety recommendations.