i would be interested in verification as well, by looking at it, i think it gets updates frequently, but i'm not sure if they are live or not, but it does seem that based on whichever information it is getting, then it is running a dead-reckoning type interpolation of where the train probably is, and there's nothing wrong with that. however, i would be very impressed at the efficiency of the flow if this was all actual readings all the time.

The interpolation was about 2-3 minutes out and in that time it didn't poll the tfl server as far as I could see. However, when I hit refresh the location was pretty accurate.