(26 Jul 2014, 1:04 pm)Andreos Constantopolous wrote Just to stick my two penneth in - why can the toc's have the system working like it has done for however many years, but bus operators seemingly can't get it right.

Two completely different solutions. Buses need to use a combination of GPS and mobile data. GPS obviously for the vehicle to work out it's position, and mobile data to transmit it to a central control centre. I don't pretend to know an awful lot about rail, but I believe the rail system tracks the unique identifier of a registered train passing different 'check points' throughout the network rail infrastructure. Metro does the same, as you'll notice the next stop announcement always triggers at the same point.