Better Mobile Reception on German Trains: How WAVETHRU™ Retrofit Improves On-Board Connectivity
- Pulsaart by AGC
- Dec 9, 2025
- 3 min read
Passengers in Germany increasingly expect to stay connected throughout their train journeys. Streaming, remote work, phone calls and constant access to mobile data have become part of modern travel. Yet anyone who uses trains regularly knows the frustration of weak or completely lost signal while onboard.
The main reason for this problem is inside the trains themselves. Modern train windows often include thin metallic layers used for thermal insulation and climate comfort. These layers protect against heat and cold, but they also block radio waves. Even when mobile network coverage outside the train is strong, signals fail to reach passengers inside.
To solve this, train operators are turning to a new type of glazing. Deutsche Bahn (DB) and regional operators such as NEB are equipping trains with windows that allow mobile signals to pass through. WAVETHRU™ Retrofit, developed by Pulsaart by AGC, uses a precise laser treatment applied directly to existing windows. The process creates a fine and almost invisible pattern in the metal coating that opens a path for 4G and 5G signals. The glazing remains just as insulated and transparent as before.
DB considers the benefits strong enough to make this a standard in its fleet. New ICE trains such as ICE 3neo and ICE L receive signal friendly windows from the factory. Older trains are being upgraded during regular maintenance and through dedicated retrofit campaigns. A pilot project began in 2022 and the rollout is now progressing at high speed. The laser equipment used for the treatment is compact enough to operate within DB workshop halls and the process is fast. A double decker coach can be completed in a single work shift.
This approach also supports sustainability goals. The windows are passive elements that do not consume power, do not require maintenance and do not need periodic replacement. The previous solution relied on active in train repeaters that required energy and frequent technical attention. These repeaters can now be switched off.
Measured performance shows a major improvement. Conventional windows often reduce external mobile signals to only a tiny fraction of their original strength. With WAVETHRU™ treated glass, trains can receive up to one hundred times more signal. The result is clearly noticeable to passengers who experience fewer dropped calls and more reliable internet connection during their trips.
The technology is spreading beyond the long distance network. In December 2024, NEB equipped its Siemens BEMU and HEMU vehicles with the new glazing. This is particularly valuable in the state of Brandenburg where wide rural areas previously had poor onboard reception. The upgrade now brings consistent connectivity to commuters and leisure travelers who rely on regional services.
After their maintenance visits, during which the windows are laser-treated, the trains immediately return to service. Passengers will thus benefit from improved mobile phone reception on board, train by train. "Several new trains in the VBB network already have windows that are more permeable to mobile signals. By retrofitting older regional trains with laser-treated windows, VBB is now bringing them up to the same quality standard as the newer trains in the network. Mobile working, streaming or reading the news on a smartphone becomes easier during the journey thanks to improved mobile reception, making the travel experience more pleasant for passengers," says Thomas Dill, Head of Department Center for Local Transport and Quality Management at VBB GmbH (Verkehrsverbund Berlin-Brandenburg).
German rail operators are transforming their trains into digitally ready environments by rethinking something as fundamental as the window. Passengers benefit through a much more reliable mobile experience and train operators gain a simple and future proof solution that supports comfort and energy efficiency at the same time.
For the millions of people who travel across Germany every day, the era of losing signal as soon as the train door closes is finally coming to an end.
