Making installed train windows permeable to mobile-phone signals

The laser treatment engraves microscopic lines in the metal coating © 2022 Alain Herzog EPFL spin-off nu glass has successfully tested a portable system that makes the window panes on railcars permeable to mobile communications. This can bring significant environmental and cost benefits to railway companies and mobile-phone operators, since they'll no longer have to install signal boosters to provide wireless connectivity for passengers. Train riders expect to have a good internet connection while on board, yet the insulated window panes currently used on trains interfere with wireless signals. For now, railway companies get around this problem by equipping each railcar with a signal booster, or repeater. But repeaters are expensive boxes that consume a lot of power, are environmentally un-friendly and must be replaced every time there's a new advance in wireless technology. To avoid the need for repeaters, nu glass has developed a laser treatment that can be applied directly to installed window panes. The company recently tested their system on a Swiss railway company (CFF) railcar at the Olten rail yard and found it can deliver substantial cost savings for railway companies and for the mobile-operator consortia that provide connectivity for passengers.