Hello,

There are some rail road companies offering an internet connection to their customers. How can they do it? What kind of internet connection can they have on board a moving vehicle?

• Satellite connection? I think the train movement will displace a mounted dish and it also will have to be constantly moved around to find the satellite as the train makes turns. Speed isn't greater either.
• GSM connection - EDGE, UMTS, CSD? 3G coverage often is not an option in rural areas where train goes. These kinds of technologies doesn't offer good speed.
• WiMax? Wikipedia article on it says it could provide 40Mbps for long distances. Is that what they use mostly?
• Some kind of power line internet carrier?