The University of Bristol (UoB) collaborated with First Rail Holdings (First) to design an architecture that enables WiFi connectivity to and from inter-city trains. In particular, the project has addressed the issue of reliable high throughput wireless backhaul to and from high speed trains. WiFi access points at 2.4GHz were assumed within the carriages to provide Internet connectivity to the passengers. This internal WiFi network is not considered to be contentious although interference with the backhaul needs to be minimised. 

First specified continuous wireless coverage, even in deep rail sidings and within tunnels. The project explored two candidate WiFi architectures that provide high capacity WiFi connectivity to inter-city trains. The first solution was based on a wireless architecture with Access Points (APs) placed regularly alongside the rail track. Each AP radiates using one or more antennas to provide connectivity to the train. This approach is referred to as a radiative solution. The second solution was based on the use of an RF leaky feeder. Leaky feeders are designed to conduct RF signals along the entire cable length. Signals then radiate over short distances through the use of regular slots cut into the cable casing. This second approach is referred to as a conductive solution. The results confirmed that radiative directional antennas perform much better than the conductive leaky feeder.