A feasibility study for the construction of a rail tunnel between the Finnish capital Helsinki and the Estonian capital Tallinn via the Baltic Sea, known as the FinEst Link project, has been completed.
The construction of the railway tunnel is slated to require an investment of roughly €13bn-€20bn.
The estimated figure includes the cost of planning, tunnel construction, the building of two artificial islands, stations, terminals and depots, but excludes the cost of procuring rolling stock.
Results from the feasibility study concluded that the project has the potential to bring multiple regional and national benefits.
Finland minister of transport and communications Anne Berner said: “The tunnel would, together with the Rail Baltica railway project and the Arctic railway line, connect the Arctic region with the heart of Europe via Finland.
“The tunnel could thus be a significant project for all of Finland and Europe, not only for Helsinki and Tallinn.”
The study found that the project could be developed via a public-private partnership model, which would see the private sector fund the tunnel building works, while a European Union (EU) grant would be required to cover 40% of the total costs.
The Helsinki–Tallinn tunnel is expected to be 103km-long, which would make it the longest undersea railway tunnels in the world upon completion.
According to the FinEst Link calculations, the service will carry nearly 12.5 million passengers and support four million tonnes of cargo movement in 2050.
Around nine million passengers currently travel between the two cities per year.
The study also defined the projected tunnel network, including stations, terminals and depots.
It will have three stations on the Finnish side at Helsinki city centre, Pasila and Helsinki-Vantaa airport respectively.
The tracks in the tunnel will have the European gauge of 1,435mm before transitioning to the Finnish standard of 1,524mm upon joining the planned airport Line in Helsinki.