On May 24, 2011, about 3:35 a.m. eastern daylight time, northbound CSX Transportation (CSX) freight train Q19423 (striking train) was traveling about 48 mph on a single main track when it struck the rear of northbound CSX freight train Q61822 (struck train), which was stopped on the track near Mineral Springs, North Carolina. The struck train was stopped at a red signal, located at milepost (MP) 313.7 near Mineral Springs, waiting for another northbound train (train 616) on the track ahead to proceed. The accident occurred at MP 314 on the CSX Florence Division, Monroe Subdivision.
In the accident, two locomotives and the first nine cars of the striking train and the last four cars of the struck train derailed. The two crewmembers of the striking train were fatally injured; the two crewmembers of the struck train were treated for minor injuries. Property damage was estimated to be $1.6 million.
CSX train movements in the area of the accident were governed by wayside signals, controlled by CSX train dispatchers in Florence, South Carolina. The maximum authorized speed for freight trains on the Monroe Subdivision was 50 mph.
The struck train left Greenwood, South Carolina, on May 23 about 11:30 p.m., following northbound train 616. The striking train left Greenwood, South Carolina, on May 24 about 12:03 a.m., following the struck train.
About 3:24 a.m., the crew of the struck train arrived at Mineral Springs and stopped the train at a red signal at MP 313.7. Train 616 was stopped in front of them at a red signal at MP 308.5.
After stopping at the signal for about 10 minutes, train 616 began to move northward after receiving a green signal. Then the crew of the struck train received a green signal to proceed, and their train was struck by the striking train.