Site of the 1987 Maryland train collision

The Maryland train collision occurred at 1:04 pm on January 4, 1987, on Amtrak's Northeast Corridor main line in the Chase community in eastern Baltimore County, Maryland, United States, at Gunpow Interlocking, about 18 miles (29 km) northeast of Baltimore. Amtrak train 94, the Colonial (now part of the Northeast Regional, from Washington, D.C., to Boston), crashed into a set of Conrail locomotives running light, and which had fouled the mainline. Train 94's speed at the time of the collision was estimated at about 108 miles per hour. Fourteen passengers on the Amtrak train were killed, as well as the Amtrak engineer and lounge car attendant.

The Conrail locomotive crew failed to slow down at the signals before Gunpow Interlocking, and it was determined that the accident would have been avoided had they done so. Additionally, they tested positive for marijuana. The engineer served four years in a Maryland prison for his role in the crash. In the aftermath, drug and alcohol procedures for train crews were overhauled by the Federal Railroad Administration (FRA), which is charged with rail safety. In 1991, prompted in large part by the Chase Maryland crash, the United States Congress took even broader action and authorized mandatory random drug-testing for all employees in "safety-sensitive" jobs in all industries regulated by the U.S. Department of Transportation (DOT) including trucking, bus carriers and rail systems. Additionally, all trains operating on the high-speed Northeast Corridor are now equipped with automatic cab signalling with an automatic train stop feature. Several safety issues were identified with Amfleet cars as well.

At the time, the Baltimore County train wreck was Amtrak's deadliest crash in the company's history. In 1993, however, the wreck at Big Bayou Canot in Alabama resulted in a much larger death toll.