In recent years ICT technology is gaining importance to the railway environment, more specific in the networking on-board of trains. One of the first drivers was the “always connected” idea for mobile users, but in the mean time this idea has evolved beyond providing pure Internet access for passengers, to a better way of managing the trains in all aspects. This includes comfort services like passenger info screens, or cost saving applications like remote maintenance and software upgrades, or security related applications like CCTV and PA. This paper discusses the most problematic issue of these services: how to establish and maintain a communication channel between fast moving trains and the ground, in an economical way.