As a countermeasure against other transit operators which have been providing in-cabin WiFi service for their passengers, JR East, a railway company operating a rapid express service from/to Narita International Airport, just announced it would start WiFi service in the train this coming October.
UQ WiMax users and Softbank Telecom’s WiFi users are allowed to use the in-train Internet service without any additional cost. For having Internet connectivity for trains on the move, JR East installed rooftop WiMax antennas onto some new model train cars. The connectivity will be dropped in tunnel sections of the route where WiMax signal cannot reach.
JR East’s Press Release: Brand-new Narita Express will debut on October 1, 2009[PDF]