Heslacher Tunnel

Slipping beneath the bustling city, the Heslacher Tunnel holds more than just traffic. It holds stories. This 2.3-kilometer tunnel, part of Bundesstraße 14, isn’t just a way to bypass Stuttgart-Süd. It’s a feat of engineering and a testament to the city’s growth. The Heslacher Tunnel officially opened on May 7, 1991. Before it existed, up to 50,000 vehicles clogged Südheimer Platz daily. Imagine the noise and fumes! The tunnel, a vital link between the city center and the Stuttgart Autobahnkreuz, drastically reduced this number to a mere 10,000. The Heslacher Tunnel burrows through the Bopser mountain’s northwest flank, connecting Marienplatz and Burgstallstraße. It even has an underground junction for Karl-Kloß-Straße. The geology of the area posed a challenge. The tunnel passes through Middle Keuper rock formations. Layers of problematic, swelling anhydrite within the Steigerwald and Grabfeld formations complicated construction. The construction took place in three phases, starting from Südheimer Platz. The first kilometer, built using the New Austrian Tunnelling Method, reached Karl-Kloß-Straße. This junction, constructed in an open-cut method, required the demolition and reconstruction of garden plots. From there, another 1.1 kilometers were predominantly bored. The Heslacher Tunnel features two escape tunnels running parallel to the main bore. Over 120,000 cubic meters of excavated earth filled a ravine near the Südheimer Platz entrance, making way for a new shooting club facility. The tunnel’s exhaust system is ingenious. Powerful fans direct fumes to a central exhaust shaft rising 80 meters above the tunnel, near Dornhaldenfriedhof. The tunnel’s entrance at Marienplatz involved demolishing and relocating a piece of Stuttgart’s history. The former headquarters of the Stuttgart tramways, built in 1893, had to make way for progress. Today, a small turret from the building stands as a reminder in a nearby green space. Interestingly, this section of the Heslacher Tunnel also houses the last bomb shelter built in Stuttgart, designed to protect up to 5,000 people. The Heslacher Tunnel is lit by 1,900 fluorescent lamps, supplemented by 162 sodium vapor lamps near the portals. Despite its single bore handling around 50,000 vehicles a day, including 2,500 trucks, the Heslacher Tunnel demonstrates high safety standards. It is equipped with modern fire safety and ventilation systems. Even so, discussions continue regarding a second bore to ease congestion, a testament to the tunnel’s crucial role in Stuttgart’s infrastructure. So, next time you pass through the Heslacher Tunnel, remember, you’re not just traveling through a tunnel. You are traveling through history, innovation, and a vital artery of Stuttgart.