We did have something before about this crossing - called Flosh, at least by the railways -
here, and there is a later piece
from the BBC» :
A level crossing has been shut for more than six months because the horn used on the new Azuma▸ trains is "too quiet".
Network Rail said the crossing, in Cononley, near Skipton, had been shut since December due to issues with "horn audibility"...
Mr Brown said: "We've been promised they will solve the problem by cutting back vegetation so people can see further up the line, but vegetation has the habit of growing back...
Network Rail has apologised for the inconvenience caused by the closure, adding it was "working to restore access across the railway at Cononley as soon as possible".
A spokesperson for Hitachi said: "All airhorns used on Class 800 trains comply with the standards that govern sound output levels, as set by the Rail Safety Standards Board.
That does have more direct from "the railway",
NR» and Hitachi (if not
LNER» ), which helps a bit. Note that NR did not say the horns were too quiet - that came from others - NR said they had "issues with horn audibility": subtly different. But the same problem remains as in the earlier reports: they make no sense. I even dug out all the applicable standards for this, and it still makes no sense.
The point here is that how loud the horn is (measured as its sound pressure level), as well as its frequencies, is a straightforward must-meet technical requirement for all trains, measured and enforced for all new ones. The numbers have not changed recently, though the applicable standards have. Dispensations from such rules are possible for existing trains if the rules change, but you'd never get one in this case for a new train.
Only recently did this appear as a discussion on railforums, and it's unusually hard on this thread to spot which posts are from insiders who know the facts. But a couple do at least potentially make sense of it. One says that the issue with Azuma horns is reliability - NR have assessed the risk that a horn doesn't sound on the high tone is so high that it pushes the risk at some foot-crossings over a threshold. These must be ones where the audible warning is necessary due to short sighting distances, and ten more have been closed as well. The other post adds that there is no whistle board in the Up direction (from Skipton), and on Google Earth there's no sign of trees that would block sighting that way (northwards).
There's no sign Hitachi agree with NR's view of this. (Maybe they are busy...) And is the same issue known for
GWR▸ 80xs? As they are the same design, you would expect exactly the same horns fitted in the same way. Also, horns on several train types have been known to stop working when stuffed full of snow, and in very cold damp weather (capable of producing icing or not). These issues are presumably down to details of the possible routes for air to be forced into the horn mounting area at speed and what's exposed to that.
