CASSELTON, N.D. -- Work is ongoing to repair and reopen the railroad tracks at Casselton after a crude oil-carrying train derailed and caught fire.

Cass County Deputy Greg Smith says BNSF crews are busy, even though it's a holiday and the temperature is about 15 degrees below zero.

Smith says the fire is still smouldering, but there are no longer any visible flames and the smoke is blending in with the exhaust from the equipment at the scene about a mile outside of Casselton.

BNSF Railway says on its website that it expects to reopen the tracks at 7 a.m. Thursday.

The BNSF train derailed Monday, prompting the voluntary evacuation of about two-thirds of the town. No one was hurt. The National Transportation Safety Board is investigating the cause of the wreck.