SEATTLE -- A collision between two train cars in Seattle's Sodo neighborhood has caused a fuel spill.

According to Gus Malonas with Burlington Northern Santa Fe, the cars rolled down the track and collided with two parked engines on another track.

The cars' wheels came off the tracks in the crash and a fuel tank on one of the engines was punctured, causing 1,000 gallons of diesel to spill in the rail yard east of Highway 99.

An engineer in one of the engines was taken to the hospital for medical evaluation.

The spill was stopped and the leak is contained at the site.

Malonas said it is not known what caused the train cars to roll own their own.