​On February 21, 2017, at 8:03 a.m. eastern standard time, Southeastern Pennsylvania Transportation Authority (SEPTA) light-rail passenger train 57 (train 57), traveling westbound on the Market-Frankford Line, entered the number 2 loop track at the 69th Street Transportation Center located in Upper Darby, Pennsylvania, and struck stopped SEPTA light-rail passenger train 67 (train 67) on the number 2 loop track. The collision and associated derailment also caused train 67 to strike SEPTA light-rail train 51 (train 51), which was operating in the opposite direction on the adjacent number 1 loop track. Train 57 was traveling about 14 mph at the time of the collision. Four people were injured (two passengers and two car operators) and transported by emergency responders to local medical facilities for treatment. The total estimated equipment damage to all involved light-rail equipment was $1.6 million. At the time of the accident, the sky was clear, the wind was from the northeast at 6 mph, the visibility was 10 miles, and the temperature was 37° F.

​We determined that the probable cause of this accident was the temporary loss of awareness and lack of proper speed control by the train 57 operator as the train entered the 69th Street station loop track.​

​We made recommendations to the Federal Transit Administration and to SEPTA.