A BNSF Railway spokesman said two slow-moving freight trains collided Monday evening in a Tacoma switching yard, injuring one person, derailing a locomotive and damaging some containers.
Spokesman Gus Melonas said about 1,500 gallons of diesel fuel spilled, but cleanup crews were working and no waterway had been affected.
One engineer was taken to a hospital for evaluation after a BNSF locomotive pulling 12 freight cars struck the side of a departing Union Pacific freight train, hitting that train about 10 cars back from its locomotive.
The cause of the accident was under investigation.
Main freight and passenger rail lines through the area were not affected.
Melonas said no hazardous materials were involved.