It appeared that the center wheel unit under a tanker car had a mechanical problem and it slipped off the tracks. A Union Pacific worker at the scene said he did not know when the damage would be cleared.
Novale Thompson said it tore up the asphalt at Hwy 88. Northwest Fire set up detours. The traffic lights were changed to flashing red.
The tanker displayed a hazardous material sign indicating it was carrying a petroleum product.