AMARILLO, TEXAS — Three freight trains collided in the Texas Panhandle before dawn Wednesday, derailing up to 30 cars and injuring four crewmembers, including two critically.

An eastbound BNSF Railway train rear-ended a stopped train, then moments later a westbound train collided with the two-train wreck, just east of Amarillo, according to the Department of Public Safety. The accident was reported shortly after 4:30 a.m.

"The wreckage was mangled up," said Sr. Trooper Chris Ray.

Joe Faust, a spokesman for Fort Worth-based BNSF, said no hazardous material spilled and that the trains were hauling flatbed cars carrying truck trailers.

The cause of the accident was under investigation, Faust said.

Two workers on the first train suffered injuries not believed to be life-threatening. Two crewmembers on the second train were critically injured and transported to an Amarillo hospital, Faust said. Names of the workers and details of their injuries were not immediately released.

Preliminary estimates indicate between 20 and 30 cars derailed, Faust said. Rail traffic was being rerouted and heavy equipment would be used to clear the tracks, he said.

Faust said there was no immediate timetable for clearing the tracks.