I put the tree data as akin to having schedule figures at a station as purely a departure time from the first station and the passenger has to work out themselves at current speed and estimated stoppage time at intermediate stations what time their train will arrive. Ie I have some data, but not enough so much of what I'm operating to now is assumption or guesswork, Is the aerodrome open or closed, are the runway STODA distances affected or not? Is it safe? *whirs up the dental drill*