Paul Corfield wrote:

Possibly - I confess to being out of the loop re the latest comms
methods for this type of data transport. I thought the bus system was
via the driver module and the docking station at the garage. Last time
I looked the buses were not "live" within the Oyster system. It's
possible the new radio and AVL system may provide this capability.

I believe you may be right there.

I suspect GSM *might* run into compatibility issues with what is
proposed with GSM-R and the ERTMS developments. I'm more probably
talking twaddle though! Cue resident expert ........

Doubt it. Millions of people carry mobile phones (GSM) past all manner
of Tube equipment daily without any (noticeable by the passenger)
trouble. Given suitably strong encryption, it needn't even use a
dedicated network.

Neil