Three international construction teams have been identified to build what will be the world’s longest road-rail immersed-tube tunnel, linking Denmark and Germany.

Denmark's state-owned developer of the 17.6-kilometre-long sub-sea Femern tunnel to Germany on March 4 locked the teams into current bid prices for up to nearly four years, while waiting for all approvals to clear on the German side.

Project owner Femern A/S plans this May to sign three binding contracts covering the immersed tube tunnel, portals and ramps and dredging. However, the contracts—together valued at around $4.4 billion—will lie dormant up to the end of 2019, when Germany is expected to be ready. Construction is expected to take 8.5 years.

Denmark’s parliament approved the scheme last April. However, German progress has been delayed by numerous objections until next year at the earliest, according to officials in Schleswig-Holstein state.

“Because of the delay of the German regulatory approval, we are in a difficult situation,” explains Denmark’s transportation and construction minister Hans Christian Schmid.“Construction work on the immersed tunnel project cannot be launched, but we want to maintain the good prices that Femern A/S received in September 2015.”

Since final bids were lodged, Femern A/S has cut the total construction cost forecast, including railroad systems, by around $1 billion from $5.8 billion. The contracts are open to renegotiation during the interim period.

The biggest contract just awarded, covering the tunnel and segment production, went to Femern Link Contractors, led by Paris-based VINCI Construction Grands Projets S.A. The team also includes various European contractors and Copenhagen-based design firm 

The same consortium, this time led by Denmark’s Per Aarsleff A/S is the preferred bidder for the portals and ramps. VINCI is also in the group. Netherlands-based Boskalis International B.V. leads Fehmarn Belt Contractors, which secured the dredging work.

The tunnel will link Rødbyhavn, in Denmark, and Puttgarden, on the north side of the German island of Fehmarn. It will include79 standard immersed-tube-tunnel elements plus 10 deeper special units to house equipment at 1.8-km intervals. Weighing around  73,000 tonnes each, the 217-meter-long standard units will be about 42 m wide and 9 m tall. When completed, the tunnel length will easily surpass the 6.7-km-long Hong Kong-Macau tunnel that is nearing completion.