In the Tube signs standards document [1], LU mentions switchable signs
(section 1.11). These have white text on a dark blue illuminated patch.
Can anyone tell me how and why these are used? And where? There are
some photos showing them in Waterloo, but it's a big station.
--
Michael Hoffman
[1]
http://www.tfl.gov.uk/tfl/downloads/...al_Dec2003.pdf