Just as a vaguely related aside...I regard as one of my best bits of
commuter navigation getting off the fast train from Harrow &
Wealdstone (platform 10) and managing to catch my connecting train
from platform 5 at Kings Cross in *five* minutes by way of the
Victoria line (possible by the fact the Vic train's doors closed a
couple of seconds after I jumped aboard and the same set of doors are
closest to both sets of routes to both mainline stations).