OK, so how does it work and has this new system been given a name as they usually do?
Presumably train approach is detected by a TC or treadle at a suitable distance, suppressed on departure, perhaps by a timer.
The topmost thing on the post looks like a solar panel to power it, the lower boxes house the speaker/electronics/battery backup (solar panel obviously won't work after dark)?
The post assembly is duplicated on the other other side of the footway (but not the other side of the line, which would be marginally better), presumably to mitigate risk of failure of a single component.
Is that an REB by the house in the distance, and if so does it play any part in the system (fault monitoring or reporting perhaps) ?
Stuart says the driver 's use of the horn is redundant, but the driver probably can't tell whether the recording is working if the volume is much lower than the train's own horn as he indicates. Unless they tell the driver with a driver's white light or similar. So the driver would presumably also sound his horn if required by a whistle board (though I don't see one),or to warn the blokes filming if he thought somebody was about to cross. Maybe just force of habit.
I don't see the usual collection of warning notices for pedestrians, probably just a case of being out of shot lower down on the fence
From John Webb's comment, perhaps it is still experimental at this stage?
Sounds like a good idea, and certainly doesn't look expensive.