FinEst Link project director Kari Ruohonen told HS that the project for the tunnel includes its route, stops, terminals and warehouses.

"A publishable design has not yet been completed," admitted, but added that it was in the process of being finalized.

The official preliminary study being funded by the EU is due to be completed by next February, which would allow construction on the tunnel to begin in the 2030s. The FinEst Link project currently involves the cities of Helsinki and Tallinn, Uusimaa Region, Harju County as well as the states themselves of Finland and Estonia.

Together with his partners, Peter Vesterbacka, the founder and former owner of Rovio, the creator of Angry Birds, has suggested another route, which would include a stop in the Keilaniemi district of Espoo. According to Ruohonen, such a possibility has not been ruled out entirely.

"They will receive all the basic data and calculations that we compile," said the project director. "Based on these, they can propose their own options."

The official survey also includes the suggestion that the terminals should be located in the vicinity of the airport, which offers convenient connects to the rest of Finland.

The survey also predicts passenger numbers through the year 2050. According to Ruohonen, the survey's forecasted ridership is fairly similar to that which has already been achieved with the Eurotunnel connecting France and the U.K.

"We also predict that passenger numbers will double or triple," Ruohonen said. "This wouldn't be reflected in current ferry traffic, which would continue to thrive. Growth in passenger traffic would simply transfer to the railway."