Work on the latest European engineering feat is well underway, with developers of the Fehmarnbelt Tunnel celebrating reaching a safety milestone – three million working hours without any accidents that resulted in serious injury.

The 18km underwater project will link Germany to Denmark, a combined car and rail crossing reducing journey times dramatically: train services between Hamburg and Copenhagen will be cut from five to two-and-a-half hours.

There will be two double-lane motorways and two electrified rail racks with a journey through the tunnel when it is completed in 2029 taking seven minutes by train and 10 minutes by car – it will be the longest combined rail and road tunnel in the world.

The €10billion crossing traverses a stretch of the Baltic Sea known as the Fehmarn Belt, and it will connect Puttgarden in northern Germany with Rødbyhavn on the Danish island of Lolland.

To cross by road at present involves a 160km detour across the Danish mainland, with the alternative a ferry service that carries millions of passengers a year. Work began in 2020 on the Danish side of the tunnel and in 2021 on the German side, a nine-year project that developers aim to make “Denmark’s safest construction site”.

“We are satisfied that we generally have an extremely low accident rate on our project,” said Gintaras Vagelas, Health and Safety manager at Femern A/S. “FBC (tunnel consortium) has approached the task with the same goal as us, namely to be Denmark’s safest construction site.”

For the corresponding three million working hours, the Confederation of Danish Employers say the average rate would be would be more than 78 occupational accidents on construction sites in Denmark