Live departure data is fetched from the National Rail website, much like my timetable site, and then it does a bit of maths and magic.
* Subject to how one chooses to define of 'exact'
I just love that. Specially creating a diagram that doesn't show the thing you want to highlight. Hats off to 'em. I'm just hoping this document was intentionally altered to make a harder test. But in these cases there's always the risk that a legitimate document really was genuinely that badly-written. Still, if so, at least I'll have plenty of rewriting work to do.