Underground railway infrastructure projects are facing delays and cost overruns

Original plans envisaged a construction period of around 20 years, with completion scheduled for 2018. The start of operations was then postponed to 2020, later to 2022, and finally to 2024. The opening of the railway therefore lagged 7 years behind the original forecasts.

Cost estimates also changed over time. The initial investment estimate was €3.814 billion, then €4.725 billion, followed by €5.373 billion, and finally the current estimate of €5.9 billion.

Tunnel under Mount Koralpe

The Koralm Railway (Koralmbahn) comprises 130 kilometres of track, more than 100 bridges, and 50 kilometres of tunnels. The largest component of the line is the 33-kilometre Koralm Tunnel (tunnel under Mount Koralpe). Construction began in 2008. Initial estimates assumed completion in 2016; here too, the completion was delayed by 7 years compared to the original plan. Costs also increased, with the key factor being significant additional expenses in excavation works.

Semmering Railway Tunnel

At 27.3 kilometres, this is one of the longest railway tunnels in Austria. The first groundbreaking took place on 25 April 2012, and construction is still ongoing, with current forecasts indicating completion in 2030.

Complex geological conditions were the main cause of delays, as the tunnel was originally expected to be operational by 2024. The delay therefore currently amounts to 6 years. Project costs have also increased from the initial €3.1 billion to €3.9 billion, an increase of €800 million.

Brenner Base Tunnel

The 55-kilometre tunnel will connect Austria and Italy under the Alps. Construction began in 2008, and the breakthrough was marked two months ago (September 2025). The start of operations is planned for 2032. Original estimates were more optimistic, foreseeing traffic by 2028. The reasons for delays are complex: from geological issues with water inflows to political indecision, as well as the termination of a contract with one of the consortium contractors.

Costs are now estimated at €10.5 billion.

Unpredictable conditions and their consequences are part of construction

In long-term infrastructure projects, especially in the construction of long railway tunnels and complex underground structures, delays and adjustments to investment values are common. Geological surprises, technological changes, supply chain disruptions, and economic conditions can significantly affect the pace of work. Such deviations are therefore not an exception in international practice, but a characteristic feature of large infrastructure projects that must adapt to real on-site conditions.

*The data are based on official publications, audit reports, and publicly available information