I don't think anyone is saying it's instant nor is that what was expected or criticised here, see:
Perhaps
@Dis86 can answer re: how long it would take from a call being made to the rail company and the track being shut down but I presume the expectation is that by the time police have been informed and someone has been able to drive to that location then that would be sufficient time no?
Ergo the comment re: reporting not being completely clear, of course, it's likely referring to suicide but what isn't clear is whether the 999 call specified someone on the tracks or as another poster pointed out someone somehow deemed to be in distress in that rough area, if it did refer to some suicidal person on the tracks in the call then the questions posed re: the person handling the call or the rail company surely apply no?