A transfer ladle wagon containing 100 t of solidified cast iron derailed at around 10 am on a slight bend on a railway track at a steelworks. The driver activated the emergency stop and the convoy went off the rails in a straight line for 116 m after the bend, before coming to a standstill. The steering bogie that detached from the wagon severed a power pole and a pylon supporting the steelwork’s two gas pipes (60% CO) located 100 m from the initial derailing point. One of these pipes (pressure: 14 mbar, diam: 2,400) ensured the supply of gas from the converters to a 60,000 m³ gasometer, and the second (pressure: 160 mbar, diam: 1,000) ensured its transfer to dispatching before upgrading in the plant’s other units. The day before, this ladle had been transported to the slag heap in order to pour out the liquid cast iron for subsequent recovery. A malfunction of the ladle rotation system had prevented the ladle from being completely emptied and the attempt to repair it with a crane from an external company after 2 pm was unsuccessful. It was therefore decided to take the wagon back to the blast furnaces in order to liquefy the cast iron which had solidified on the walls of the ladle. The accident occurred during this trip. The internal emergency plan was activated, gas circulation in the pipes was interrupted and their integrity was checked. According to the hazard analysis, a severing of the pipes could have caused the release of 5,278 Nm³ of gas for the 2,400 diameter pipe and 1,249 Nm³ for the 1,000 diameter. The train driver was treated in the sick bay. The shifting of the wagon’s load caused the accident. The operator must update its hazard analysis and plans to move the pylon out of the reach of any consequences of a derailment and upgrade the incomplete protections on the other pylons. Production losses were estimated at €44,000.