A structural issue has been identified in Talgo's Avril S106 high-speed train units, which were ordered by Renfe, Spain's national railway company, for several billion euros. The problem was first discovered when maintenance teams found a crack on a unit at the level of the bogies, the chassis on which the wheels are fixed. As a precaution, Renfe removed the other four units from service that were operating on the Madrid-Barcelona line operated by Avlo, Renfe's low-cost brand. The issue has raised concerns about the safety and reliability of these high-speed trains, which are a key component of Spain's rail network. According to the Spanish press, similar defects have been observed on other units running on other high-speed lines such as Madrid-Valence. Sources close to the file cited by La Razon reported that two additional units had to be removed from service by the end of August. This has caused concern among drivers, with their main union sending letters to Renfe and the National Railway Safety Agency, demanding new safety measures. The union warned that if the structural integrity of the bogies of the S106 units cannot be guaranteed, appropriate measures must be taken on the equipment, however drastic they may be. Talgo initially stated that the cracks were not due to poor design or fragility of the train but were the result of the poor condition of the tracks between Madrid and Calatayud, where vibrations exceed the limits allowed for a journey at 300 km/h. However, it is now clear that these cracks are not caused by the tracks but by the units themselves. This revelation has added pressure on both Renfe and Talgo to resolve the issue quickly, as all high-speed activity of Renfe is affected by this problem. This may lead to penalty claims from Talgo, who has already had to pay an indemnity of 116 million euros due to delivery delays. The issue also affects Le Train, a company planning to offer a high-speed service in western France, which has ordered 10 units from Talgo for 350 million euros. Le Train's president, Alain Getraud, previously stated that the malfunction "does not change its plans," attributing the problem to the track rather than the train. However, this argument no longer holds, as the cracks are now believed to be due to the units themselves. It is not known whether Talgo has started production of the units for Le Train or whether the company has completed its fundraising to finance its order. Talgo stated that the homologation process for the S106 is continuing in France, although Renfe had stopped the process on its side after suspending its project for a high-speed link between Spain and Paris. Homologation is an essential step to obtain authorization to run a train on the network. Talgo maintains its agreement with Le Train and stated they will work together to manage the necessary procedures. Without homologation, Le Train could face difficulties in obtaining the financing expected for several years now to buy its trains.