In message , Richard J.
writes

Also, he didn't choose the colours on the 1933 original. They were the
same as on the existing geographic maps of the network.

Not entirely. Stingemore, who designed the Underground's maps in the
years immediately before Beck, used orange for the Central Line, red for
the Bakerloo, brown for the Met and a sort of greyish aquamarine for the
Piccadilly. Only the Northern (black) and District (green) were the same
as Beck. Shades also varied quite a lot. Beck chose stronger tones and
insisted on much better colour control in the print process.

--
Paul Terry