In message , at 22:54:54 on
Wed, 21 Mar 2012, John Salmon remarked:

The two main departure boards each have 20 panels, showing the next 18
departures or departures for the next 90[*] minutes, whichever is the
fewer; the 19th and 20th panels are summaries of departures and
arrivals, but with no 'headings' to show which is which - you just
have to know, or be capable of working it out.

It's true - they've forgotten (or decided not) to add those 'headings'
to these boards, which are commonplace elsewhere.
--
Roland Perry