The infrastructure arm of OEBB (Austrian Federal Railways) and its contractual partners have reached the halfway point for the 27km Semmering Base Tunnel.
Works are continuing during the coronavirus pandemic under heightened safety regulations.
“Almost all of the ÖBB-Infrastruktur construction sites are up and running again. With regards to the Semmering Base Tunnel works were able to continue without interruption but with some limitations. We've of course applied the given safety measures such as wearing masks and keeping appropriate distances.”
Although all the construction sites for the Semmering Base Tunnel have remained operational throughout, some supply shortages and quarantine situations among the workforce have led to some limitations in certain areas.
Coronavirus Safety Measures
To ensure that construction sites could remain operational, the construction firms developed measures for safe working during the coronavirus pandemic together with safety experts, occupational medicine experts and ÖBB-Infrastruktur. Measures include maintaining a safe distance, hygiene requirements, arriving at the construction sites separately, adapting work process and changing shift plans.
“We've thereby managed to keep important parts of the economy going. It's very clear that investments in rail infrastructure are a major and important engine for jobs, both now, but specifically after the crisis too. With more than 90 percent of the value being added at home, we're having a big impact and we're directly contributing to the regional economy.”
Half the Semmering Base Tunnel is Dug
Despite the unique working conditions the Semmering Base Tunnel has reached a milestone: taking into account all access routes, shafts and connecting tunnels, a total of 62km of tunnel must be dug for the 27km tunnel. After eight years of digging, the halfway point has now been reached.
Ground-breaking on this major project took place in 2012 with the actual digging beginning in 2014. The Semmering Base Tunnel is being constructed from five location simultaneously. Most construction sites needed access tunnels and shafts to be built first before the actual tunnels could be built. In 2019 then the works on Mürzzuschlag Station began. The tunnel is to be completed in 2027.
Tunnelling
The two tunnel boring machines (TBMs) Carl and Ghega are digging their way through the mountains towards Gloggnitz from the Fröschnitzgraven construction site at the centre of the tunnel. Both Carl and Ghega have now completed more than towards Gloggnitz. A further 3km have been achieved between Fröschnitzgraben towards Mürzzuschlag. In this direction, however, the tunnel is being built with the more flexible ‘new Austrian tunnelling method’ (NATM) or ‘sequential excavation method’ (SEM). This method is also being used at the Grautschenhof construction site near Mürzzuschlag. At that location both tunnel pipes have been excavated by around 1.5km in both directions.
Tunnelling is a particularly challenging undertaking in Lower Austria. Major efforts are under way in Gloggnitz to stabilise the tunnel. In spring 2019 there had been mud ingress. The team in Gloggnitz is preparing for the installation of the inner shell. The workers in Göstritz meanwhile are continuing their work with additional measures to manage water.
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