At 8:40 PM on the evening of July 5, 2019, westbound manifest 34A derailed the first 11 cars as it entered the main arc of Horseshoe Curve. The three locomotives remained on the rails and the crew was unharmed. Track One remained open at restricted speeds as contractors began the cleanup process.
34A was 141 cars long. The first 11 cars were empty, and there were no rear helpers.