Stephen Furley wrote:

On some stations there's a railway 'phone in a metal box, with a
notice saying that it can be used by passengers to contact the
signaller to obtain information about train running. I've seen these
at stations on the Settle-Carlisle line, which runs through some very
remote areas for example.

The first series of Michael Portillo's Great British Railway Journeys showed a
level grade crossing near a station with a sign and a phone requesting that
individuals crossing with animals call before crossing the track.