Leading company in global industrial gases and engineering Linde has officially launched the world's first hydrogen refueling system for passenger trains in Germany’s Lower Saxony state. In this context, Vallourec supplied high-pressure pipes to Van Halteren Technologies in Boxtel for the manufacturing of piston accumulators intended for the Bremerhaven refueling station of the Buxtehude-Cuxhaven train line. Back in August 2022, Linde inaugurated the world's first hydrogen refueling system for passenger trains in Germany’s Lower Saxony state. The system will supply 14 Coradia iLint hydrogen-powered passenger trains in the town of Bremervörde, Rotenburg district. With a single refueling, the trains will be able to run 1,000 kilometers and are expected to gradually replace the existing diesel-powered fleet. With a total daily capacity of around 1,600 kilograms, the hydrogen refueling system was built with the ability to integrate future on-site green hydrogen generation. Van Halteren Technologies in Boxtel, a specialist in hydraulic systems and mechanical engineering, approached Vallourec for the supply of high-pressure pipes for the manufacturing of 64 piston accumulators intended for the Bremerhaven refueling station of the Buxtehude-Cuxhaven train line. The piston accumulators will contain up to 1,800kg of hydrogen at a constant pressure storage of 500 bar. This is an alternative design to refueling by pressure drop which is the most common system using cascades of hydrogen cylinders. By comparison, piston accumulators require an additional hydraulic circuit, but allow full use of the storage volume and minimize the number of tanks needed. For Van Halteren Technologies’ request, Vallourec provided 64 pipes in 460mm outer diameter and 40mm wall thickness. Thanks to its mills across the globe, Vallourec has the ability to provide customers with large dimension pipes up to 710mm and thick walls up to 110mm, providing designed thickness to withstand high pressure, even after machining and finishing. Wide capability range allows for tailor-made and optimized solutions, helping customers to optimize the dimensions in an effort to maximize the storage system’s overall cost efficiency. Vallourec’s pipes delivered to Van Halteren Technologies were manufactured in grade 34CrMo4+QT, a grade qualified by Vallourec for hydrogen high-pressure storage. Vallourec also provided quality heat-treatment (quenching and tempering) as well as a customized surface finishing specially adapted for its application, i.e. the piston accumulator was produced with the required extra smooth surface finish including tight shape and position tolerances to ensure high hydrogen pressure tightness and precise piston movement.