Indeed. Labelling “revolutionary” might be pushing it somewhat when passengers, and also staff, have had access to sites such as Real Time Trains and Open Train Times for a good few years now.
This is quite interesting (well, to people like me

).
The hard part is automatically identifying what train you're on. In theory you can do "map matching", which takes your GPS position and current timestamp, compares it to a database of railway geometries and current train running, and gets the result from there. But it's pretty complex. There's a startup called Signalbox (
https://www.signalbox.io) who are doing interesting stuff in this space.
I wonder if Whoosh are short-circuiting this by using a
QR▸ code. If the QR code is distinct for the train in question (say, 800316 or whatever), then the app simply needs to look up the current running for that unit, without faffing with map matching at all.