Out of curiosity, does anyone know why communications don't work on the london underground? In Newcastle upon Tyne we have a light rail system called the metro. parts of it are overground, but in the cities (Newcastel and Sunderland) it's an underground system. I can get a clear mobile signal underground on the metro, although I've got to admit I don't know off the top of my head if emergency services radios work down there. I would expect so though. Surely it wouldn't be that difficult to invent a way to make underground comms possible? Where are all the techs whose job it is to invent these things?