A preliminary investigation conducted by the National Transportation Safety Board into Norfolk Southern's fiery Lincoln, Alabama train collision has placed blame on a misaligned switch.

The NTSB released those findings Thursday just hours into their investigation. The report says the incident occurred at 16:22 EST, when NS train 22R, with NS GP60s 7137, 7138, and 7143, struck the rear end of autorack train 226, which was hauling cars from the nearby Mercedes-Benz plant in Vance, AL.

A total of four cars from the autorack train, all three locomotives and an undetermined number of cars on the 22R were derailed and/or destroyed. A resulting fire, fueled by diesel from the locomotives and the contents of the derailed cars, was left to burn out on Thursday.

Two of the cars in the second train were carrying sodium cyanide, a hazardous material. Air monitoring tests did not detect the chemical, said Susan Terpay, Norfolk Southern spokeswoman. Three Norfolk Southern employees were injured. Terpay said the injuries were not life-threatening.

The investigation will focus on how the mainline siding switch, controlled by a dispatcher in Atlanta, Georgia, was set for the siding and how the train that was supposed to pass it on the mainline, collided with the standing train.