Who hasn’t been there? You’re sitting on a train, about to send an important email or stream your favorite show—and suddenly: dead air. As soon as the train enters a tunnel, most mobile networks give up in the face of concrete and rock. On the Magistrale für Europa, that’s soon to be a thing of the past—at least in the area of the Rastatt Tunnel.
At the entrance to the Rastatt Tunnel, a 40-meter-high cell tower has recently begun to rise into the sky. Birte Naamnih from the Karlsruhe–Basel rail project is overseeing the initiative and knows: This tower is anything but “standard.” The steel structure weighs a full 50 tons.
The problem? The location. The mast sits atop a steep embankment. If it were simply placed there, its enormous weight would press directly onto the tunnel’s trough structure and, in the worst case, damage it.
The engineers’ solution is as invisible as it is ingenious: The mast is anchored twelve meters deep on four massive bored piles. These completely decouple the mast’s weight from the tunnel structure. It stands, so to speak, “above” everything and guarantees stability without straining the infrastructure.
The Nervous System Beneath the Ground
But the mast is only the visible part of a complex system. Right next to it are two massive concrete switch houses that form the heart of the facility:
- Emergency Radio (BOS): One switch house is reserved exclusively for non-public radio. It facilitates communication between emergency services and the railway—essential for safety in an emergency.
- Public mobile communications: The second building ensures that passengers remain connected even at 250 km/h.
How does the signal reach the tunnel? The switch houses are connected underground. Inside the tunnel itself, so-called radiating cables do the job. These function like kilometer-long antennas that evenly distribute the signal throughout the entire tunnel.
A win for the entire region
The project is a prime example of how modern rail infrastructure also benefits the surrounding area. In addition to passengers on the European Main Line, people in the surrounding area also benefit from significantly improved network coverage.
Now that the mast in the north is in place, the next step is to install its counterpart in the south. Once both “heroes” are active, the digital gap at the Rastatt Tunnel will finally be closed. A small step for the passenger, who simply continues browsing—but a major engineering feat behind the scenes.
Source: DB Infra GO: Karlsruhe–Basel Rail Project