How could this incident have happened? “For our part, there are sequencing hypotheses that seem coherent to us,” says Matthieu Theurier, vice-president of transport for the metropolis. A metal component of a metro train came loose, explains the elected official, due to the loosening of a nut. This element then came into contact with the electrical power line, fixed in the floor of the tunnel, causing a short circuit in the signal box.
“Judicial expertise”
But the ecologist remains cautious. “I’m wary because everything is contested by everyone,” he breathes. The debate is still ongoing between, on the one hand, Siemens Mobility, designer of line B, and, on the other, Keolis Rennes, responsible for its operation and maintenance. For Keolis, there is no doubt: the incident was caused by a design error. Especially since on January 3, 2024, this same nut failed on another train, causing a second stoppage of line B, even more prolonged. It took five months to replace the suspect parts on the 25 metro B trains. Siemens took the opportunity to change the nut model to prevent the problem from recurring.
For Siemens, on the other hand, the matter is not settled. “The manufacturer argues that there were maintenance errors,” explains Matthieu Theurier. Has Keolis committed any breaches? When contacted, Siemens Mobility did not go into details. “Regarding the incidents that occurred last year, the legal expertise is still in progress and does not call for any particular comment,” this subsidiary of the German giant told Telegram. She adds: “Siemens Mobility worked hand in hand with the Rennes metropolis and the operator to bring line B back into service, which has been taking place since June 20 without major incident. »
Line B still closely monitored
The stakes of this battle, now on the “judicial” ground, are not a mystery: “there are insurance issues”, deciphers Matthieu Theurier. But the debate, he specifies, does not directly concern the Metropolis. The community did not have to pay for the repairs, which were covered by one or the other of the two companies. Certainly, it considers that it has suffered financial damage: rebates granted to subscribers, loss of revenue linked to lower than expected attendance, etc. At this time, however, the Metropolis has not initiated litigation with Siemens.
Returned to service on June 20, 2024, line B continues to be closely monitored. The State requires an inspection of new parts every 5,000 km on the two trains that have been driven the most. Or check at least every week. More advanced stage points must also be carried out at 30,000 km then at 150,000 km. “The repairs were completely satisfactory,” assures Matthieu Theurier. Who clarifies: the few breakdowns that have occurred in recent months are not linked to this famous nut, at the origin of so many twists and turns.
