Two photos from the amazing, huge pickmix.co.uk site, collecting photographs from the London Transport Museum’s archive. On the left, in a 1977 colour print by Paul Proctor:
The experimental press-button Passenger Route Indicator machine installed in the ticket hall at Heathrow Central (now Heathrow Terminals 1,2,3) Underground station. The indicator incorporated a TV screen designed to display a diagrammatic route map of the chosen journey.
And to the right, a 1974 photograph by H J Hare & Son:
A passenger consults a route indicator machine at Oxford Circus Underground station. Oxford Circus services Central, Victoria and Bakerloo lines.
You can see more of my favourite images from the site. See also: a similar map in Paris.