Phone calls on track

Passengers traveling on Rhine-Ruhr Express trains in Germany will soon benefit from improved cell phone reception – thanks to a trio of inventors from Vienna.
Inventors of the Year 2018

Outstanding Invention

What we were looking for was a solution that is cost-effective for rail operators and also brings them long-term advantages.
Mehrdad Madjdi, Lukas W. Mayer, Andreas Demmer, Mobility and Corporate Technology

It’s extremely frustrating when you’re sitting on a train and the connection keeps breaking up in the middle of an important call. This happens because train carriages act like giant Faraday cages, from which radio waves simply bounce off. Mehrdad Madjdi, Lukas W. Mayer and Andreas Demmer have developed a special structure for windows that reduces their shielding effect and considerably enhances cell phone reception.


The breakthrough innovation is of real benefit to passengers. From the end of 2018, travelers on Rhine-Ruhr-Express trains in Germany will enjoy a much improved cell phone reception. The geometrical pattern on the inner side of the double-glazed window panes, almost invisible to the naked eye, is made up of metal-free lines which a laser has cut out from the pane's coating. The innovative arrangement of these lines allows radio signals to pass through practically unhindered, so enhancing reception significantly. The project was initiated by Mehrdad Madjdi from the Mobility Division in Austria, who sought the collaboration of his colleagues from Corporate Technology in Vienna.


“What we were looking for was a solution that is cost-effective for rail operators and also brings them long-term advantages,” says Madjdi. Previous attempts to improve cell phone reception in train carriages had involved the installation of radio amplifiers. But, as well as being expensive and energy-intensive, devices of this kind need to be replaced every few years.


Due to findings from the aviation sector, the high-frequency experts at CT already knew that radio waves are more easily able to penetrate cabins with certain types of window structures. “Concluding that the degree of permeability depends on how the gaps in the metallic layer are configured, we developed patterns that could be cut out with the aid of a laser,” explains Mayer. A manufacturer of carriage window panes was then commissioned to produce prototypes for installation in a test carriage belonging to the Austrian Federal Railways (ÖBB).


Following on from the Rhine-Ruhr Express, contracts have now been signed with Czech Railways and Austrian Railways.