The longest railway tunnel near Plzeň will be excavated next Saturday

Plzeň - The second tube of the longest railway tunnel in the Czech Republic - in Ejpovice near Plzeň - will be penetrated next Saturday, October 7. Only the last 50 meters remain to be dug. The end of the tunneling machine at the exit portal in Plzeň-Doubravka can be watched by the general public. The complete tunnel, costing 2.5 billion crowns, will be finished by December 2018. This was stated by Milan Majer from the investor's Railway Administration and tunneling manager Štefan Ivor from the construction company Metrostav.

The first tube, measuring 4.1 kilometers, was dug for 16 months until June 11 last year. The excavation of the second one began exactly a year ago. "Thanks to the experience from the first tunnel, we already knew what to expect and how to prepare for it. The excavation went almost without problems," stated Ivor. Part of the cutting head of the machine, named Viktoria, was revealed today. Next Saturday at 10:00, people will see the last centimeters of the excavation. "Nowhere in the world has the machine emerged like this to be visible for a week," said Majer.

The remaining excavation will last from today for four days. "People can come and watch from the viewpoints on both sides and see the machine digging," said the main site manager of Metrostav, Václav Anděl. From October 3 to 6, from 19:30 to 21:30, videos of the excavations will be screened at the portal.

In recent days, occasional booming sounds have been heard from the construction site, caused by blasting work during the construction of the last two of eight safety connections between the tunnels; the classic Austrian tunneling method is being used. "For the first two-thirds of the excavation under the Homolka hill, we were moving in slates, where the tunnels were dug with an excavator. The last two connections were in hard speleothems, where excavators wouldn’t have stood a chance," Ivor said. Initially, the whole tunnel was to be excavated using explosives. Eventually, however, a tunneling machine was chosen, so local residents were not restricted in any way.

In the tunnel, the filling concrete still needs to be completed. Additionally, sidewalks with cable ducts must be poured with concrete, and then a solid track bed will be laid at the bottom.

The tunnels, which are up to 35 meters apart, will be the main part of the new double-track line from Rokycany to Plzeň, which will also be completed by the end of 2018. This is one of the final sections of the III. railway corridor Prague - Plzeň - Cheb. The cost of the project has increased from just under four billion to about five billion crowns. "The most expensive additional work was related to the tunnel, as we encountered worse geotechnical conditions and had to adopt a number of measures. All of them are justifiable and part of the contract," Majer stated. A permanent supervisor from the State Fund for Transport Infrastructure has been overseeing the project since the beginning of last year, who must approve everything.

According to Majer, there were several factors that made the construction more expensive. At the beginning, there was an archaeological survey that delayed the project by a year. Another problem was water and hard rocks. The builders knew about the speleothems, but did not anticipate that they would wear down the cutting heads so much in conjunction with the water. Strong mineralization of the rock also acted like magnets, stopping the conveyor belts carrying the rubble.

Discussions are now ongoing regarding the further use of the German tunneling machine TBM worth hundreds of millions of crowns that Metrostav purchased. "Currently, there is no construction in the Czech Republic where it could be used," said the builders.