The Chicago Transit Authority has tried for years to come up with names for the 'el' lines that would make it easy for tourists and riders to decipher.
I've lived here long enough to remember Congress-Douglas, Howard-Englewood-Jackson, Lake-DanRyan, Ravenswood, Evanston Express, and Skokie Swift.
Those morphed into Congress-Douglas-O'Hare, Howard Dan Ryan (there was a short-lived and ill-fated attempt to abbreviate that as "Ho-Dar"), Lake-Englewood-Jackson (calling that "LE Jack" was similarly short-lived), Ravenswood, Evanston, and Skokie. Then Midway was added.
Its current incarnation is colors. In order of the above names, it is Blue Line, Red Line, Green Line, Brown Line, Purple Line, Yellow Line, and Orange Line. The Pink Line is the newest. Trouble is, we're running out of colors. If they add any lines, we'll have to use names like Chartreuse, Apricot, or Soylent Green.