This palette is based on colours used by the London Underground for some of their tube lines: Jubilee (Pantone 430), Metropolitan (Pantone 235), Northern (Pantone Black), Piccadilly (Pantone 072) and Victoria (Pantone 299). colourlovers
The first diagrammatic map of the Underground was designed by Harry Beck, an Underground employee, in 1931. He drew up the diagram in his spare time while working as an engineering draughtsman at the London Underground Signals Office. London Underground tentatively introduced it to the public in a small pamphlet in 1933 and it immediately became popular. The Underground has used topological maps to illustrate the network ever since.