TULSA, Oklahoma - The Burlington Northern Santa Fe Railway and the FBI are investigating a major derailment in North Tulsa and offering a $100,000 reward for information.

It happened early Friday morning and crews were still on the scene in the evening. A two-mile stretch of the track has been closed all day. Tulsa Firefighters were called because 100 gallons of fuel spilled into a nearby creek. People who live nearby say they heard a loud boom. The railroad believes it all started with vandalism.

According to a news release Friday evening, BNSF Railway Police believe someone tampered with a parked train's air brake system around midnight on Thursday.

"There have been incidents before where some equipment has been released," said Joe Faust, with BNSF.

One of the trains was headed to California from Tulsa when multiple rail cars detached from the rest of the train. BNSF spokesperson Joe Faust said it appears as if the part keeping the rail cars together was removed.

"We believe that the coupling device was removed from the train, so right now we're treating this as an act of vandalism," Faust said.

Those 57 runaway cars crashed into another BNSF train that had just arrived in Tulsa from Chicago.

"These trains were secure the whole time," Faust said. "The reason that the train was stopped at Trenton Street was because it was a crew change point."

The train headed to California was filled with Kia vehicles. Faust said one of the two locomotives involved in the accident was destroyed.

The conductor and engineer were able to get off the train before the collision.

"The Chicago into Tulsa train that was parked behind it saw some signals and when that signal went from green to red, they knew something was not right and they were able to get off in a timely manner," Faust said.

By the time the sun came up, derailment crews were busy cleaning up the wreckage. They used heavy machinery to move the mangled rail cars and workers built replacement tracks.

Burlington Northern is calling this a "major derailment."

"This is BNSF mainline track, so we are impacted. We are in the process of rerouting our trains throughout the area," Faust said.

The track is expected to be open and running by 3 a.m.

If you have information about the derailment, contact the Crime Tip Hotline for BNSF Railway Police at 1-800-832-5452.