Guardian journalist Bim Adewunmi recently traveled from London to New York and slammed the subway as compared to her beloved Underground. The blowback has been delightful. She seemed especially angry about the information system that isn't exactly what Transport for London would do.
The city’s subway map is dense and needlessly complex. Where in London the Central line (red) is distinct from the Piccadilly (dark blue), which is markedly different from the Hammersmith and City line (pink), New York’s map has designated the same forest green to the 4, the 5 and the 6 lines. The B, D, F and M all rejoice in exactly the same shade of violent orange. ... Why would you do this? The whole thing resembles a child’s approximation of a city transit system: it makes no sense.
She's talking about branching lines. If she were from Paris, whose elegant Métro is nearly branchless, she'd have a point. But what a comment for someone from London!
In New York's map, the common color helps you navigate the core part of a line while the numbers or letters help you sort out the branches. This is a very common way of making branching lines clear. Meanwhile, in London, where transit is presumably designed by sober adults, we have this:
No 4, 5, and 6 to confuse you! No, just a beast called the Northern Line even though it's both northerly and southerly, consisting of two entirely different lines through the central city. Is there a direct train from Waterloo to Mill Hill East? How would I know? As Clive's Underground Guide helpfully explains: "The pattern of service ... tends to change with each new issue of the timetable."
You see, Bim, Americans like maps and nomenclature systems that actually indicate where their train will go! In London I'm sure you just somehow just know what the next Northern Line train might be up to. But all that aristocratic just knowing that you Brits do is exactly why you lost your Empire!