As Far As I Can Tell

Ever since moving to Chicago I’ve been baffled by the color coding system used on the CTA trains. There are various El lines, each labeled by a different color name, and shown on the map in that color. The confusion is that each station has signage and other branding in a color that doesn’t necessarily match the color of the lines that it services. I’ve been keeping a close eye on it, and trying to spot a pattern — any pattern — but I haven’t found anything. Last night I found my explanation.

Starting in 1948, the CTA had something called the A/B system. Each stop was an A, a B, or an AB station. Likewise, each train either stopped at only A, only B, or all stations. In the original A/B signage the letter code of each stop was printed directly on the signage for that station. The colors at this time were all black text on a white background.

In 1977 the “K-D-R” A/B signage system was implemented, which added to the text a color indicator as to what type of stop the station was. Red was an A, green B, and AB was blue. This worked well, and was much more visible from a distance. It’s important to note that the different train lines had not yet been assigned colors of their own.

In 1995 the A/B system was abandoned, and all trains now stop at every stop. Also in the 90’s, the lines were given colors of their own, along with their names. So the O�Hare/Forest Park line is now also known as the Blue Line. The use of color to denote different lines is useful, but unfortunately the colors overlap the colors used for the now extinct A/B signage. This results in stations such a the Fullerton stop, where all the signage is blue (because it used to be an AB station), but it services the Red, Brown and Purple Lines.

Luckily the CTA has gotten plenty of criticism over the inconsistencies, and has created new signage called The Current Graphic Standard. The new visual system has consistent gray backgrounds, and stripes on each end for every color of line that the station services. In my opinion this is exactly how it should be. Unfortunately they are only replacing older signage as it needs to be repaired, and there is no general overhaul of the signage system planned.

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I learned all of this from Chicago-L.org, an extensive site detailing the history of the Chicago El trains, including system maps back to 1898.