Duck Mountain Tunnel
The Entenberg Tunnel is a 288 meter long railway tunnel in the Thuringian district of Eichsfeld , which is located on the Dingelstädt – Schwebda railway line , which was opened in 1880 and which was part of the so-called “ Kanonenbahn ” and has been closed since 1998.
location
The Entenberg Tunnel, built in 1878, lies between Großbartloff and Lengenfeld under the stone half in a straight line (west), half in a curve with a radius R = 400 m (east) with a continuous gradient of 1: 101. The tunnel entrance is at route km 27.931 and the tunnel exit is at route km 28.219. The mean altitude of the tunnel is 303 m above sea level . It runs in the steadfast mountains of the lower shell limestone and has the most favorable geological conditions of all tunnels on the route. The tunnel was extended by 7 m to the north around 1915 and a new concrete portal was built. The overburden is up to 30 m, the area above the tunnel is overgrown with beech forest. The tunnel went into operation when the route opened on May 15, 1880.
history
When construction began, there was little experience. It is not known in which construction method the tunnel was built, but it can be assumed that it was built using tunneling, like the first Thuringian tunnel near Förtha, what later became known as the “Austrian method”. The abutment and vault masonry was made from limestone and sandstone quarries. The stones were extracted to a small extent during the tunnel excavation and processed on the spot. Sole vault is not available. The tunnels were not initially sealed. From around 1910, this was done in sections with the simultaneous offset of the cavities that had remained open above the vaults. This structural defect was the cause of a lot of damage that occurred after just 20 years. Moisture penetration of the non-insulated masonry led to the washout of the grout and damage from frost chipping. Fin quarries in unstable mountain sections resulted in vault and abutment deformations. As early as the turn of the century, numerous repairs were necessary, most of which were made of clinker masonry. Inadequate workmanship could often be identified, but the biggest mistake was that the masonry was in principle too weak in accordance with the complicated geological conditions. Up until the beginning of the 1940s , extensive repairs and renovations were necessary almost every year. Then there was hardly any maintenance work for more than a decade. From the mid- 1950s , the tunnel was thoroughly repaired and damaged masonry was replaced with considerable effort.
The tunnel is part of the railway line of Lengenfeld unterm Stein after Küllstedt that today with Handcars can be driven.
Position of the tunnel portals
- North portal ( 51 ° 13 ′ 36.5 ″ N , 10 ° 12 ′ 16.3 ″ E )
- South portal ( 51 ° 13 ′ 28.2 ″ N , 10 ° 12 ′ 14.1 ″ E )
