Submission - Historical Map: Chicago CTA Rapid Transit Map, 1983

Submitted by our resident repository of Chicago transit map knowledge, Dennis McClendon, who says:

This map of Chicago’s rapid transit network originated in the 1970s (this one is from June 1983), and this style was used until routes received color names in 1993. Happily, by that time digital printing in fiberglass-embedded signs made full-color maps easier to place in graffiti-prone environments.

These maps were silk-screened onto [blue] color blanks, and every color of ink added cost. So the CTA’s six lines are represented by using only two colors. Simple black is used for three “extension” lines that never overlap. A simple white line is used for the north-south line those connect with. For the two other through routes: black with white casing and white with black casing.

The side ticks for stations work fine, but a box for the places where transfers are possible is not altogether intuitive.  The CTA of that era employed skip-stop spacing, so alternate trains stopped at A or B stations only. Another graphic decision that might have deserved more thought:  the names of various suburbs—only a few of which can be reached by rapid transit—floating in their vague geographic positions, but no indication of Chicago city limits or Lake Michigan.


Transit Maps says:

I have to say that I actually really like the forced graphic simplicity of this map. There’s only two colours to work with, so every element has to be very carefully considered and balanced against others for the map to work at all. That it manages to keep the route lines recognisable and separated in the downtown Loop area without the use of an inset map is quite an achievement.

The famous “A-B” stopping patterns are shown pretty deftly as well, being mostly placed on the opposite side of the route line from the station name. The few stations where this doesn’t happen (due to crowding or space limitations) stand out like a sore thumb – Jarvis on the North-South line, and many of the stations on the Ravenswood line. There are also two stations with their labels set at an angle: Merchandise Mart is almost completely unavoidable, but Harvard on the Englewood Line could easily have been fitted in horizontally.

I think the “boxed” interchanges work well enough, having seen similar devices on quite a few maps (the Paris Metro included) now. I also like the extra detail included on the map: station closures on weekends and nights, direction of travel around the Loop, inbound boarding only on the last three stations on the Jackson Park North-South Line, and more.

I would agree with Dennis on the locality names, that just seem to float in space. The biggest offender is “Evergreen Park”, right at the very bottom of the map, below the legend!

As for depicting Lake Michigan, that seems like a good idea, but I struggle to think of a way of doing it without upsetting the delicate balance of the map. You can’t really use a white line, as that could be confused with all the white route lines, and you can’t have a large white area as that would be visually way too heavy. In the end, the lake isn’t that important for such a graphically stylised map (it really just delineates the eastern side of the map), so I’m not too upset by its absence.

Our rating: A fine historical example of how to use a limited colour palette effectively. Minimalist but still effective. Three-and-a-half stars.


Behind the Scenes: Evolution of the Chicago CTA Rail Map from 1996-2006 and Beyond

This material was sent to me via email by Dennis McClendon, who runs Chicago CartoGraphics, a design firm in the Windy City that specialises in maps and information graphics. His email — which outlines his role in the development of the Chicago “L” map as used in the CTA system map brochure (the first link on this page) — is so fascinating that I’m basically reproducing it in its entirety below. In effect, Dennis is Transit Maps first guest writer!


A little inside history on the CTA map:

I took over the CTA system map (the folded paper citywide map showing all buses and trains) in 1995. The “cover side” of the map was produced by an internal graphics department and had all the bus schedule info, how to ride info, and a diagrammatic train map.

Transit maps are a longtime passion, and I had quite a collection from around the world. I thought the diagrammatic train map CTA was using (Image 1 above) was embarrassing, and asked permission to redesign it. I was told they’d “take a look.” So I spent a Saturday trying a couple of different approaches. Since the 1980s, I’ve had a London Underground Journey Planner on my office wall for inspiration, so I first tried a very Beck-like approach for grins (Image 2). But it just didn’t feel like it belonged to Chicago.

I had a hazy memory of a map CTA had used, probably only on carcards, in the late 1970s or early 1980s, but there were no examples of that left around the system. Nonetheless, that memory guided me to try fat color lines with white circles for stations. One of the main innovations I wanted to introduce was the “hollow dumbbell” to show transfer points in an instantly comprehensible way. At the time, CTA was using a circled T to indicate transfer points—and those survived as a sort of belt-and-suspenders thing.

One strange thing about CTA is that different departments do maps for the paper system map, maps displayed at train stations, and the maps over the doors in the trains (carcards). I only produced the one on the paper system map, which was also provided to guidebook publishers (and soon turned into neckties and shower curtains, and used on a variety of marketing and branding materials). CTA soon imitated my diagram, however, for the station maps and carcard maps (though they would not give up the “T for transfer” on the carcards). The typeface began as Helvetica, which has a strong heritage at CTA, then changed to Frutiger Condensed (Image 3) on recommendation of an outside consultant (to my delight, since I’m a big Frutiger fan); then reverted to Helvetica after that design firm disappeared.

One particularly tricky thing in Chicago is the orthogonal nature of the city, whose gridded streets run absolutely straight for 25 miles.  Chicago has five rapid transit stations called “Western,” and there’s a natural inclination to see them line up. That limits the spatial distortion that can be introduced, yet the downtown area has many closely spaced stations. CTA always preferred, therefore, to have an enlarged inset for the Loop area. I’ve always maintained a “unitary” version (Image 4), however, that I use for other tourism clients, sometimes in other typefaces. I also figured it would let me sidestep copyright issues with CTA.

I lost the CTA system map contract to another company in 2007 (though I recently got the RTA contract). Meanwhile, Graham Garfield at CTA assumed oversight of all customer information, finally putting all the different maps under one boss. Among many other things, he’s a design aficionado, but I don’t always agree with his decisions. He put the highly accurate gridded maps into the stations rather than the diagrammatic map; I think his feeling was that it helps give riders more context of the city around that rail system. (The latest version of this map was reviewed on Transit Maps here)

This not-so-diagrammatic map (Image 5) is the one on the [brochure PDF on the] CTA website these days as well. The carcards, however, still retain the diagrammatic look.

An element I always thought was important was having the station names in the same color as the lines, so I was surprised that the most recent system map changed that. The wheelchair icons got fussier, and readers are now insulted with the notation “Map Not to Scale.” As a cartographer, I also cringe to see “Lake Michigan” not in italics. I asked Graham about that over lunch recently, and he mumbled something about italics being harder to read.


Submission - Historical Map: Chicago Regional Transportation Authority, 1977

Submitted by Dennis McClendon, who has previously submitted material related to transit mapping in Chicago that I’ve featured on the site.

This map is a real beauty, and I definitely appreciate Dennis’ ability to talk about the technical aspects of cartography in the days before computers. We take computer-aided design almost completely for granted today — but map-making was a laborious, manually performed task back then, where a scalpel, a light box and rubylith film were vital parts of a cartographer’s arsenal.

I’m just old enough as a designer to have come in at the very end of this manual era of printing. My very first task in a real design studio was to cut up 48 pasteboards to mount the artwork for 24 double-sided leaflets on. I then marked up each and every board on an overlay with the colour specs for every element and instructions for stripping in photos from colour transparencies, or “trannies” (yes, really):

Tranny X - enlarge to 143%, crop as shown. Strip to keyline, delete keyline.

For every photo on every page.

But enough reminiscing about the olden days: on to Dennis’ thoughts on this fantastic map:


Because I’m hard at work on its modern successor, I thought you might be interested in a very curious and striking printed map from the 1970s: the famous black Chicago RTA map, first published in 1977.

This was the Chicago area’s first full-color transit map, a splashy beginning for the newly created Regional Transportation Authority that voters had approved to take over the region’s failing transit agencies and private companies. The colors used for the Chicago Transit Authority rail lines would—mostly by happenstance—be chosen 20 years later as the actual names for those lines (brown got swapped with purple for the line serving Northwestern University, whose school colors are purple and white).  Transit history geeks will understand the A and B symbols on the rapid transit stations as relating to Chicago’s skip-stop service (ended in 1995) during which alternating trains stopped only at A or B stations.

The system map exhibits several traits long associated with Chicago transit maps, such as the curving corners, dots at terminals, and bare route numbers next to the lines.  There are reminders of the era, like the Souvenir Bold Italic typeface used for points of interest.  The map was designed by Rand McNally, and the folklore is that they were hungry for the work. The same oil crisis that had boosted interest in public transit had made free gas station maps unnecessary, and that was a big part of Rand’s business. But the main design question is: why black? Printing a rich black generally requires two passes, or at least an underlayer of cyan.

The official explanation for the black is that it was a clever way to deal with misregistration of thin colored lines.  Undoubtedly there’s a lot of truth in that.  In those days of Scribecoat and photomechanical production, cartographers had to worry a lot about trapping and misregistration. So a close look at the thin blue and tan bus lines will reveal that a one point line has been photographically “spread” into a 1.4 point line that is behind a 1 point gap in the black (black is printed last in four-color printing). The method wasn’t always totally successful, and there are tiny white gaps around some of the point-of-interest names.  But an ordinary 1 point tan line would have been difficult to print, since it would be composed of a 20 percent dot each of cyan and magenta, and a 30 percent dot of yellow—all of which would need to line up exactly.  None of the colors would so dominate that the other colors could be “choked” to a narrower line that wouldn’t peek out.

Some of the printing details can be seen in the enlargement.  The rich black seems to be 100% black over 40% cyan.  The ocher-olive (not the most pleasing color, even in the earth-tone 1970s) looks to be about 60% black over 60% yellow.  A similar combination of cyan and black produces a handsome steely blue for the downtown inset.

A very curious design feature is that bus lines are never allowed to intersect.  Instead one line is always broken where another crosses it. Some of this was worked out by folks who knew the system well, and buses on overpasses, or buses making a 90-degree turn, are always shown on top of crossing lines. The others were randomized like a basket weave. The reason for this design choice isn’t obvious to me; it may be that it reinforces where lines turn a corner and where they continue straight. There doesn’t seem to have been a production rationale: at least one perfect uninterrupted crossing (Kimball and Peterson) is shown, apparently by mistake. The idea of color-coding bus lines by which rapid transit line they feed wasn’t a success.  Lots of crosstown lines reach four different lines along their lengths, and many crosstown bus riders aren’t headed to a rapid transit line at all.

But back to the main question, why black?  I never saw another example anywhere of a black transit map—except for Métro inset maps on Montreal’s maps in the 1980s, which were so obviously reproduced directly from the artwork used for panels inside the cars that they even include the warning not to interfere with the functioning of the doors.

I think the real reason was marketing. The RTA was a new agency that saw the value of graphic design to tie together the region’s disparate transit assets and build public support for them.  The maps, the signage typefaces, even the livery on locomotive, railcars, and buses was what we would today call “branding.” So while there may have been a good production justification for the striking black RTA map, I think the bigger reason was how cool it looked. Indeed, I had a copy hanging on my wall when I was in grad school a thousand miles away, never dreaming that 30 years later I’d be the designer trusted to make a new RTA system map useful and attractive.

Watch on

Video: Making Vitreous Enamel Wayfinding Signage

As an aside to the last post about the 1983 Chicago CTA map, Dennis also sent along this fun little “How It’s Made” video about the process used to create signs such as this.

In the case of the CTA signs, the background blue would be the second layer applied to the steel signboard, and white and black would be the two screen printed colours that are then fired and fused permanently to the backing. It’s a time- and labour-intensive way of making signs (largely replaced by full-colour digital printing today) but it’s absolutely fascinating to see the process involved.