Prag Tunnel

The Prag Tunnel is a railway tunnel in the German city of Stuttgart under the Prag, a ridge between the Stuttgart basin and Feuerbach. The two 680 metre-long bores of the tunnel connect Stuttgart North station with Feuerbach station. Trains from Stuttgart run through the tunnel towards Karlsruhe, Mannheim and Heilbronn on the Franconia Railway and the Mannheim–Stuttgart high-speed railway and towards Ludwigsburg and Leonberg on the Stuttgart S-Bahn.

The tunnel runs in layers of Gipskeuper rock, containing anhydrite, which swell strongly when in contact with water. The track centres in the two tubes are 3.70 and 4.00 m apart.

The first tube of the Prag tunnel was built as part of the first railway in Württemberg, the Württemberg Central Railway between Esslingen, Stuttgart and Ludwigsburg. The first sod was turned on 26 June 1844 and marked the start of the construction of the Central Railway. Five shafts were sunk to enable the construction of the tunnel running through the Keuper layers; these were later filled in again. During a tunnel collapse 20 workers lost their lives.

The 828.65 metre-long tunnel finally broke through after two years of construction and operations began on the Central Line on 15 October 1846. The tunnel was designed from the start for two-track operations, but it initially only had a single track. The second track was built between 1858 and 1861.

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