Train derailed south of Seattle, rail carriages fall on US motorway.

Two train carriages have plummeted on to a motorway in Washington state leaving a number of casualties.The train derailed about 64 kilometres south of Seattle before 8 a.m. Monday, spilling at least one train car on to busy Interstate 5.

Images from the scene show emergency services treating people on the ground. Amtrak confirmed there had been injuries.Several cars on the highway were struck by the derailed carriages, the Pierce County Sheriff’s department says.

There are multiple injured motorists, it added.

Local news stations report that this was the inaugural run of the new high-speed rail line.

Before the crash, it was travelling at more than 80mph (130kmh), with at least 75 people aboard.

The National Transportation Safety Board is investigating.