Sunday, March 14, 2010

Subway Map II

(Subway Map I is here.)

Subway Map II: Express or Local

One of the thorniest problems with a New York subway map is how to show express and local services. It is not enough to show lines and stations: you also need to show that some trains skip some stations.

What I'm saying might sound obvious or simple. I want to state the obvious first, and then show you why it's not simple at all.

On a four-track line, express and local trains both stop at an express station, and only local trains stop at a local station. And on a two-track line, all trains stop at all stations.

Subway stopping patterns are very closely tied to the physical structure, the arrangement of tracks and platforms. When a train comes to a station platform, it stops. Express services are run where there are third and fourth tracks that do not run next to platforms at some stations.

It doesn't have to be that way. The Metro North, Long Island, and New Jersey Transit systems schedule many trains to run past platforms without stopping. There can be a great variety of stopping patterns, some unique to one train, so it is not useful to show them on a map.

On the subway however there is great regularity. An express station has platforms facing all the tracks ; a local station does not. This is so standard that it something feels slightly wrong when the paradigm does not match the train service. For example, some elevated sections have a third track not used in normal service, but some of the stations have platforms facing the third track and some do not, and they feel like express and local stations even though there is no express and local service.

The strangest anomaly is DeKalb Avenue station, Brooklyn, where there are six tracks, four of which run past platforms. To force it into the standard paradigm, it is usually understood to be an express station with bypass tracks.

I'm running through all this stuff just to suggest that the idea of express and local stations has something to do with the way they are built, not just the train service that is offered.

Let's see what the mapmakers did.

The influential maps were the company maps of the Interborough Rapid Transit system and Brooklyn-Manhattan Transit system, and then the first map showing all subways, created by the Hagstrom company.

The Interborough company's map led the way by using two types of circle to show local and express stations. The fine detail exceeded what cheap color printing could handle, as seen here in a very late example from 1937. The Brooklyn company's designer improved on the idea by using simpler circles, but overloaded the circles with a second feature showing where the company thought passengers should transfer between trains. Hagstrom adopted the best of both ideas: simple circles.

But what do we do on an outer section of line where trains stop at every station? What are those stations? They aren't express stations, because there is no express service, but they aren't local stations either, because calling them local stations would imply that some trains skip them.

Let's see what the mapmakers did with that.

Here's the IRT company map showing part of the west side line. Reading the map from the bottom, only local trains stop at 86th St and 91st St, express and local trains stop at 96th St, and then... what happens at 103rd St and 110th St? Only local trains, or all trains?

Maps by Geographia, Hagstrom, and Voorhies all follow the convention of the IRT company map. These all date from about 1936 to 1940.

Hagstrom eventually changed to show 103rd and 110th as express stations.

What did trains really do? Up to 1959, there were four services up to 96th St, and an express and a local went to each branch. The locals ended at 137th St (Broadway) and 145th St (Lenox), and the expresses continued to the end of the line. North of 96th St, all trains made all stops.

But how should this be shown? As interpreted by the old IRT map and its followers, the express station symbol implies that there are both express and local trains on the segment. As eventually reinterpreted by Hagstrom, the express station symbol means that express trains stop, meaning that trains that run express somewhere stop. That idea actually falls apart in places, but we'll get to that later on.

The Transit Authority map, 1964. By this date, all local trains ran up Broadway and all express trains ran up Lenox. Therefore, the local station symbol, a crossbar, is shown at 103rd St and 110th St (Broadway), and the express station symbol at 110th St (Lenox).

The Transit Authority's 1967 map showed stations by a box containing the markers of trains that stopped. This lets us see that the 1 train is the only one stopping at 86th St, and the only one stopping at 103rd St and north, while the 2 and 3 skip 86th St, and so on.

One of the things the Transit Authority were doing starting in 1967 was de-emphasizing the categories express and local. There were getting to be numerous trains that ran express in part of their run and local in another part. They were hard to categorize. Thus under this model, the 1 is not so much the local as it is the only train that stops at 86th St.

But there was a holdover: the reason the name of 96th St is in red is that it is a station where both express and local trains stop. That's what the old dotted circle really meant. A stop where both express and local trains stop.

The Vignelli map eliminated the boxes and the red names. You could see graphically that only the 1 stopped at 86th St, because only the 1 had a dot in its color line at that location. The boldface name at 96th St tells us that it's a stop for both express and local, although that's also clear from the dots. For a case where boldface adds something not already clear, keep reading.

The current generation of official map— this is an early version from 1980— went back to different symbols for express and local stations but finally introduced a third station symbol to code those special stations that have both express and local trains. Is this the right way to do it?

Why is 103rd St a tick and a 110th St (Lenox) a solid circle? The difference shows us that somewhere else the trains at 110th St (Lenox) run as express trains. It's almost a throwback to the pre-1967 maps. The difference is just that the different symbol for stations with both express and local makes them stand out a little— although Hagstrom did that by making the express circle a little larger, something so intuitive that it's not mentioned in the legend. That's nice design.

Now, would I beat a dead horse? Sure.

Here's another similar case, the BMT line under Fourth Avenue, Brooklyn. It's a four-track line to 59th St, and then it splits into two branches. The service has not changed since it opened: the locals continue down Fourth Avenue to 95th St, and the expresses turn into the Sea Beach branch (to 8th Avenue and off to the right side, in all these maps).

The BMT map handled this exactly like the IRT map. It looks like the express trains stop at 36th St, 59th St, and then run past the next stations. A difference is that the 95th St branch is so short that you can guess at a glance that only local trains run there, since even the last stop is local only.

The stations with double rings seem important, and especially the ones with black centers, but you'll need to read the legend (reproduced up above) to find out why.

Note in passing: the BMT map has another feature not explained in the legend. The width of the line corresponds to how many tracks there are. There are sections with two, three, and four tracks in the view above.

Not surprisingly the Geographia, Hagstrom, and Voorhies maps all follow the convention and show the Sea Beach stations as local.

And once again, Hagstrom's reinterpretation eventually showed the Sea Beach stations as express stops. Notice that 36th St and 59th St have larger circles.

The Transit Authority map follows the same convention.

The 1967 map (this is a 1968 edition) gets the same idea across with the RR and N train markers in boxes. The special stations for both express and local are named in red, as we saw before.

The Vignelli map runs into a problem. Because the yellow N train was now scheduled to make the local stops at 45th St and 53rd St at night, its line has dots at those stations. The boldface names at 36th St and 59th St clue you in (or do they?) that those are stops for both local and express trains, but which train is the express? Unless you knew the insider code (no longer in use today) that a single letter N is express and double letter RR is local, you'll need to read the small-type service guide, or pay attention when you ride.

The reality of a train being express and local at different times is hard to code on a map, and I don't want to knock this particular solution too much. The idea on the Vignelli map was to that if a train made the stop at any time, put the dot.

In Subway Map I I raised the question of what level of detail to show on a system map. Maybe all that needs to be shown is that there are both express and local trains, because that clues in the reader that not all trains make all stops. Maybe the detail of which trains make which stops, at different times, is more than we need to show on a system map. Keep that in mind.

The current generation of map shows 45th St and 53rd St more clearly as local stations, and handles the N express or local through a convention of listing the train markers at every station. The boldface italic N means it always stops, while the plainface N means it sometimes stops. But whether you get that or not, you definitely get the idea from the map that there are express and local trains on that section, and that's the main thing.

Let's take another case of trouble with part-time patterns. We don't need to go way back for this one. The Brighton Beach line was pretty simple up to 1967: both express and local at Prospect Park, Church Avenue, and Newkirk Avenue, and local in between. The express did not run overnight. The usual express and local symbols told this story, on the BMT map, the Hagstrom map, and the others. Here's the 1964 Transit Authority map. (The extra line at Prospect Park is the Franklin Avenue Shuttle.)

Then the reroutings of 1967 made it get interesting.

Here on the 1968 map, it looks like the D and QB and QJ trains all make all stops. Wait, no, the red names indicate stations with both express and local service, and some are not red. So, some trains skips those black stops. Sometimes. That seems to be what it says.

The Vignelli map is just as unclear. Dropping the dashed lines for special rush hour services looks nicer but gives the barely-there QB equal billing with the other two services (now called D and M), which makes it even harder to guess what the service here is.

Should that much detail be on the system map at all?

The current generation of map does a much better job of differentiating the local-only and express-and-local stations, by using the big open circles. If you can interpret the train marker code at the station names, differentiating plain type from bold italics, you can even figure out what is going on with the train service. The D is the one that skips some of the stations, right?

This is another case that is very hard to show graphically. What we've got here is both express and local service on weekdays, and only local on nights and weekends. That's not too hard, but the marker D is the express when there is an express and the local when there is only a local. If we were not so concerned about showing the marker letters, maybe it would be easier to show the main point that there are both express and local services.

An odd result is that the local stations show three train markers with none in boldface italic— no train stops there 24/7. But there is some train service 24/7! That's more important.

(By the way, even with better registration than we have on this particular copy, it looks like the M is separated by whitespace from the other two line colors. I don't know why. If anything is to be separated, it should probably be the orange D that runs sometimes as an express.)

You know something, there are even crazier things that have to be shown on a New York map. But for that, you will have to wait till next time.

The 1937 IRT and BMT maps are from Mapping New York by Seth Robbins and Robert Neuwirth, London: Black Dog Publishing, 2009. The Hagstrom maps from 1936 and 1956 are from Twelve Historical New York City Street and Transit Maps by John Landers, Flushing NY: H & M Productions, 1997. The rest are from my collection.

For a long time there were two basic Hagstrom maps. The large one, our 1936 example, was sold in Hagstrom's line of pocket maps, and while it was the official subway map (1940-1958) it was posted in cars and stations. The smaller one, our 1956 example, was used as a foldout in guidebooks published by Hagstrom and others.

Next time: Subway Map III.


  1. Over time on the subway maps, there has often been a confusion about whether a particular train route is local or express; and whether a station is local or express, or all stop. For example, on the #2 line it is local in the Bronx, just like the #1 line where both use three track stations with side local only platforms. Plenty of maps will show the #1 stations as "local stations", and the #2 stations as "express stations" even when physically the stations are same physical type. There are plenty of other examples on the maps over time. This was a through discussion of the issue, keep up the great work.

  2. This was a really interesting read, and very helpful to a project I'm working on. Thank you.