Having extra feeds increases the redundancy of the system, Thornton says. "If one of the possible feeds isn't working, then you've got a spare." Different beams could also be enlisted for different services, he says, noting that one could be used to provide live television while another is used for Internet access.

Ratul Mahajan, a researcher with Microsoft's networking group who has been working on wireless Internet connections for cars, questions why Thornton chose to use satellite Internet instead of 3G, a telecommunications standard that's becoming common in cellular-telephone networks. "Why use satellite at all?" Mahajan asks.

Thornton says that 3G currently doesn't have the kind of geographic coverage required for continuous Internet access along train routes. Upgrades to the cell network, he says, tend to be concentrated in towns. "Each base station can only offer the highest data rates to users typically one or two kilometers away, so a truly vast number would be needed to cover all the railway routes in a country the size of the USA, or even France," Thornton says.

Thornton is currently trying to find a commercial partner for his system but admits that it's not ready to hit the rails just yet. In fact, it has yet to be tested on a moving vehicle. The team still needs to develop a control system and protocols for handling multiple satellite feeds.