A one train car derailment in Knoxville blocked all north and south traffic in town for nearly an hour this afternoon. At approximately 12:15pm one car on a Burlington Northern Santa Fe train traveling east through Knoxville fell out of line and off the track. An onlooker noticed the problem and called in to report the derailment and the train was stopped to inspect the situation. The train stretched through Knoxville and blocked all intersections including highway 14. The Knoxville Police Department and Marion County Sheriff’s Deputies were on hand to control traffic in the area. According to railroad officials the derailment could have been caused by heat expansion or a misalignment at one of the track switches. Crews were able to break the derailed car free from the rest of the train and move the remainder of the cars forward in order to clear the intersections. Railroad officials will have to move the derailed car back onto the tracks in order to continue east on the track. No injuries were reported.