With more than 5,000 posters, the London Transport Museum has one of the largest poster archives in the world. From January 6 to March 18, 2012, it will host a retrospective exhibition titled "Painting by Numbers - Making Sense of Statistics" [ltmuseum.co.uk]. As part of the museum's Poster Parade, the collection will include 20 original London Underground posters dating back to the early 20th Century.
As an interesting twist, all these posters are also up for sale.
For instance, "Speed" by Alfred Neete (1915) provides an interesting view on the actual speeds of the most popular transportation means back then (i.e. ranging from 1 to 24mph), "These vehicles are carrying 69 people" promotes travel by bus back in 1965 with 3 different photos taken on top of a fire engine tower. Already in 1923, the persuasiveness of data and statistics already encouraged graphic designers to eclectically combine different data points, as the poster "And What It Takes to Move the Passengers" demonstrates, as it contrasts the number of staff with the weight of coal with the gallons of oil required to transport 306 million people a year. Finally, we can already recognize the less than efficient practice of colorful though text-focus, relatively ineffective infographics in the poster "Figures for 1923".