PORTLAND, Ore. -- A Union Pacific train jumped the tracks in downtown Portland early Sunday morning.

Several cars in the freight train came off the tracks near Union Station, causing the railroad crossing gates to drop near 9th Avenue and Overton.

Drivers along Naito Parkway should expect detours for most of Sunday morning.

The derailment is not expected to affect Amtrak's train schedule.

There were no injuries reported.

The cause of the derailment has not been released.