The driver of a tractor-trailer who died after colliding with Amtrak’s Downeaster in North Berwick, Maine had a checkered driving record that included two citations for unsafe operation of a commercial vehicle.The New Hampshire Department of Public Safety says 35-year-old Peter Barnum of New Hampshire, also had six speeding tickets and one seatbelt violation in New Hampshire and Massachusetts from 1992 to 2009. Spokesman Jim Van Dongen said Barnum had one accident and no license suspensions. He described Barnum’s driving record as spotty but “not disastrous.”In addition, Maine officials say he was cited twice for speeding.The truck driver was killed in Monday’s fiery collision in North Berwick. Four passengers, along with the Amtrak engineer and an assistant conductor, were injured.A Public Safety Spokesperson says witness accounts and 200 feet of skid marks indicate the driver did try to stop before colliding with the train. Investigators aren’t sure how fast Barnum was going before slamming on his brakes. The cause of the accident remains under investigation.