When the fixed link over the Fehmarn Belt opens, Denmark will have a new, fast main railway line between Scandinavia and Germany. It has long been promoted as a green boost: more freight trains, fewer lorries, and shorter transport times. However, a new status review indicates that the green effect risks being less than planned because delays and capacity issues in the railway give lorry traffic a head start.
The report is made by the consultancy firm Sweco for the transnational cooperation STRING and Greater Copenhagen, and reviews 15 specific bottlenecks in the railway between Scandinavia and northern Germany. The point is simple: the tunnel can provide trains with a shortcut, but only if the rest of the railway can handle more and longer freight trains.
German railway lags behind
Sweco's status shows that almost all of the 15 bottlenecks are either unresolved or on track to be resolved too late in relation to the opening of the Fehmarn link. The biggest challenge is not the tunnel itself, but that there is a lack of capacity in several places along the route. Some sections are single-track, others lack electrification, and several junctions are already overloaded.
Particularly on the German side, there is a specific delay close to Fehmarn. The Fehmarn Sound Tunnel, which is to carry trains further north towards Lübeck and Hamburg, is expected to be completed around 2032 at the earliest. Until then, the railway relies on an older bridge with limited capacity. This means that trains will not have free passage further into Germany, even when the Fehmarn tunnel is ready.
Further south, the railway junction in Hamburg is under pressure, and the Hamburg-Hannover route is described as one of the most congested in Europe. In Sweden, major expansions on the main lines are only planned far into the future. Overall, Sweco points to a system where the tunnel becomes a strong link in a chain that still has weak points.
Danish railway is on board
In Denmark, Sweco assesses that they are well on their way to getting the railway ready towards Femern. Especially around Copenhagen, where new overtaking tracks are being established at Kalvebod and the capacity at Copenhagen South and the airport is being strengthened, so freight trains can run more stably when the connection opens. At the same time, the Ringsted-Rødby/Holeby route is expected to be completed with double tracks, higher speed, and longer crossing tracks around 2029. The biggest Danish uncertainty is Ringsted, where several lines cross each other at level, where a new terminal is needed.
Delays do not just move a date
The report also states that the Femern Belt connection can no longer open in 2029, as previously planned. There is still no new official opening date, and this delay is important in relation to the climate effect.
The transport market does not change automatically when a new connection opens. Freight forwarders and logistics companies reroute when they see a stable and competitive solution. If the railway cannot deliver this at the opening, the market chooses the safe alternative, which here is the lorry.
This is the mechanism Sweco warns about. The longer it takes for trains to run efficiently throughout the corridor, the more time road transport has to grow into the new connection. New routes, contracts, and investments are built around lorry transport, and once they are in place, they are difficult to shift back to rail.
Road wins more than rail
Sweco's previous analysis from 2023 assessed that rail freight over Femern would only increase moderately towards 2040, while road freight is expected to grow significantly more. The status report from 2025 shows that the development has not improved. On the contrary, several of the key projects have been further delayed, and 2.5 years have passed without the progress that should have made the railway ready in time.
This means that the Femern connection in the first years after opening may have an effect that resembles the opposite of the political goal: more lorries on the new route and a smaller shift to trains than assumed.
Smaller green gain
None of the report's conclusions state that the Fehmarn Belt connection is not a good idea. It is described as a historic opportunity to strengthen rail freight in Northern Europe. But opportunities are time-sensitive. If the trains only fully benefit from the connection much later, the green gain becomes smaller because the market has meanwhile adapted to road transport.
Therefore, Sweco's message is sharpened: The fixed link can still become a green turning point, but only if the pace of railway expansions is increased and if countries coordinate better so that capacity comes simultaneously. Otherwise, Fehmarn risks becoming a shortcut that lorries benefit from the most.
