An Amtrak train from Portland derailed Sunday because the train's high speed triggered a derail switch as the train approached the Chambers Bay drawbridge, Amtrak officials said Thursday.

Several people were injured when the train derailed near Steilacoom, Washington, about 45 miles south of Seattle. The train was traveling through a section of track that contains a switch that protects an approaching bridge, according to Amtrak.

The derailment was caused by human error, said Vernaé Graham, an Amtrak spokeswoman. An engineer failed to slow the train down to the 40 mph speed limit, activating the derail switch, she said.

Three of the train's 267 passengers suffered minor injuries, Graham said. Some were transported to a local hospital and released. The remaining passengers were evacuated from the train and provided with alternate transportation, she said.

The engineer was suspended without pay, Graham said in an email.

The Associated Press contributed to this report.

— Samantha Matsumoto

503-294-4001; @SMatsumoto55