The 8,806 m long Boßler Tunnel, which runs between portals at Aichelberg and Buch (Filstal valley) in the “Albaufstieg” section of the new Wendlingen − Ulm railway line, is the new line’s longest and most technically challenging. The two single-track, circular-section main tubes with a mean gradient of 24.3 ‰ are linked at 500 m intervals by 17 cross passageways...