The explosion was discovered when a BNSF dispatcher received a switch malfunction alarm. When employees investigated, they determined the building housing the controls had been severely damaged by an explosion.
Subsequent investigation by the BNSF police and the Kane County Sheriff's office determined the damage was caused by an explosive device, believed to be a pipe bomb, which was apparently dropped into the building through a roof top vent.
The blast caused a major disruption of rail traffic for several hours to the BNSF Aurora line, which carries both freight traffic and Amtrak passenger trains, the release said. No injuries were reported as a result of the blast.
Anyone with information is asked to call the Chicago FBI at (312) 421-6700 or the BNSF tip line at (800) 832-5452.