The last 2 tanker cars, nos. 26 and 27, of a freight train transporting hazardous substances derailed around 7 pm in the vicinity of the Orthez rail station. Car no. 26 carrying 45 t of propane was on flipped its side below the track, while a liquid-phase leak was spilling onto the pipe, which subsequently ruptured.

A 100-m safety perimeter was set up and the personnel and patients at both a hospital 50 m away and a clinic 200 m away were kept indoors (233 individuals, 190 of whom were patients). Rail traffic was halted in both directions, and electrical supply of the catenaries was cut. Two trains transporting 65 passengers were also blocked; travellers were placed under the authority of emergency services, and some of them were transported to their destination by coach. Fire-fighters installed a 50-cm foam blanket underneath the overturned railcar and plugged the LPG leak by 8 pm; no presence of gas was detected thereafter. The authorities requisitioned a large-capacity flare device and broadcast information messages to local residents; a 120-t rail crane was shipped from DIJON. Passenger traffic between TARBES and DAX was transferred onto coaches. On 25 November, car no. 27 was placed back on the track and evacuated by 10:30 pm. Using the flare to burn gas from the overturned car began on 26 November at 12:30 pm under the protection of fire hoses, including nozzle guns, and ended on 28 November at 8:15 am. The car tanker was then inerted with nitrogen before being placed upright with the help of the 120 t crane after disassembling the catenaries. Rail traffic was reopened on 30 November once the track had been repaired over a roughly 50-m stretch and the catenaries restored to good working order.