Rail lines were back open Monday at the site where an Amtrak train derailed a day earlier, but slower speeds were in place. The cause of the derailment was still under investigation.

There were no serious injuries or fatalities after the Amtrak Cascade train with 267 people on board derailed near Chambers Bay in Steilacoom Sunday.

Amtrak said the train was headed north when it derailed at the Chambers Bay Bridge in Steilacoom. West Pierce Fire Battallion Chief Scott Adams said responders found four of the train's 15 cars had derailed.

Passengers were evacuated from train 506, and Pierce Transit buses took them to the Tacoma Amtrak station.

Back at the derailment site, a Gig Harbor Police Boat Patrol helped deploy pollution booms. Adams said there was no fuel leak from the derailment.

Lakewood Patrol and Marine Service Unit was at the scene assisting, along with Coast Guard and other crews. The cause of the derailment was under investigation.

Gig Harbor police tweeted video of the derailed train.