All warning systems were operating correctly at the time of Katie's accident.

BBC: Train death Katie Littlewood 'did not look' at crossing

Cross-examining Mr McKay, lawyers acting for Transocean got him to agree that Deepwater Horizon had been "a very safe operating rig" but only "up until the accident".

BBC: BP 'egregious' for drilling Macondo oil spill well

Since the accident, the transit authority has stopped using a computer system designed to avoid collisions and is operating the trains manually, leading to delays.

CNN: NTSB says train detection system failed in days before D.C. crash