Thursday, April 17, 2014

Our overloaded subways

As I wrote a couple of weeks ago, there are times when building new transit is not warranted. In particular, it is a waste of resources to build new radial capacity on the outskirts if it connects to a trunk line that can't absorb that capacity. I looked at the train crossings into Manhattan to see which could add trains in the peak. That information can suggest where to add branch lines. But what about extending existing lines or encouraging infill development?

The NYMTC's Hub Bound Travel Study has some useful data, but first it's important to give some context. They have an estimate for space per passenger, but it's only broken down by sector, not by line. They do have counts of train cars and passengers by line, so we can get passengers per car. The problem with that is that the cars are different sizes, so there is a lot more free space in an R train car with 341 people than a car with 308 people on the #4 train.

I don't know exactly which equipment was used on which lines in 2012, so I used the most recent train models I knew of. I couldn't find floor area figures, so I used the listed capacities. Please feel free to consult the spreadsheet and suggest revisions. (Edit, April 27: this chart is in fact inaccurate. Please see the comments below for threestationsquare's helpful observations.)


Here is an updated chart based on Table 20:


There are some additional questions that come to mind looking at the chart. If the demand for a line is low, is that always because it doesn't serve enough homes on the outskirts? Maybe, like the J train, it doesn't serve enough jobs. Maybe, like the R train, it's much slower than the alternative. Would extending these lines really get people out of their cars?

There is another question: yeah, an A train car with 713 people on it is really uncomfortable, but isn't a B train car with 429 people pretty uncomfortable too? This is why we need to continue to think about how we can offer comfortable alternatives to wasteful, dangerous individual car trips.

12 comments:

capt subway said...

Low ridership on the J/Z is because, bottom line, they are just too damned slow. The trains run at about 5 MPH between Crescent St & Cypress Hills - excruciating; also slow from Alabama to south of EP? Bdway Jct. Plus, there are just too many local stops. Leave Jamaica, make 25 local stops and you're at .... Marcy Ave! No surprise the Archer Ave subway siphoned off passengers from the J line with people back riding from as far away as Cypress Hills to change for the E, and thus overloading the already loaded E.

There is capacity in 63rd St. You could literally double the number of trains. The only problem is you need to build a new line somewhere in Queens.

Ditto there is capacity for one more local service on the Queens Blvd local tracks. Problem is, there is no terminal capacity at 71/Cont. The solution is a new line branching off from the QBl local tracks. A line branching out from Woodhaven Blvd under the LIE to Queens College? A line branching out after 63 Dr onto the old LIRR Rock Line? Both this would work.

threestationsquare said...

@capt subway: If the problem is lack of turnback capacity at Forest Hills, run some of the local trains to 179th St (where there is plenty of capacity) and turn them back there.

You could also increase service to the Astoria Line by running the Q via 63rd to Queens Blvd Local and the N/R to Astoria (eliminating the awkward situation of three services sharing the 60th St tunnel), but that's not really where extra capacity is needed.

capt subway said...

The problem would still remain essentially the same at 71/Cont as you would still need to "clean out" (i.e. get all the passengers off) the trains of one or two of the three services there before the trains can proceed into the lower level relay tracks or lay up to the yard. So too there is the issue of the crew change, which creates no end of problems, especially when crews are "out of place", i.e. not on their regularly scheduled trains due to some previous delay, etc.

Three local services on the local tracks would be about 30 TPH. Right now they're running around 20 TPH in the peaks and the trains are backed up a to around Grand Ave during those times. That's why the ideal solution is a new branch line, such as the LIE Line out to Queens College, which was in the original MTA master plan back in the late 1960s, or the LIRR Rock Line, which has been around sine the IND Second System master plan.

As to 63rd St: it's got the capacity but unfortunately both 6th Ave & BMT Bway are at, or near capacity. And remember the Q is slated for 2nd Ave. Which means something like the W will need to be brought back eventually. A full length 2nd Ave subway, or even one just reaching as far south as 42nd St would provide a southern terminal of an additional 63rd St / Queens service, as the original scheme from the late 1960s called for a connection from 63rd St southbound onto 2nd Ave. The bell mouths for this connection are there.

queenstransit said...

What's 33RD on the table?

Alon said...

Are you sure you're reading the numbers right? There is no way there are 341 people on each car of an R train. The Tokyo-area commuter trains have about 300 people on a 20-meter EMU. The R is not the Yamanote Line.

threestationsquare said...

@capt subway: The "clean out" could happen at 179th for some trains. The Queens Blvd line is four tracks all the way there; there's no particular reason every local needs to end at Forest Hills (though some need to, for the yard).

@cap'n transit (re Alon's comment): It looks like the numerators in the graph are total (both directions) passengers per day from Table 5, while the denominators are inbound cars 7:00-10:00 only. You should be using the numerators from Table 14B instead. Table 20 of the report itself asks a similar question and gives passengers-per-car numbers ranging from 68 to 162 for the 8:00-9:00 peak.

threestationsquare said...

@queenstransit: Midtown PATH.

Capn Transit said...

I don't know, Alon! I put a link to the numbers in my post so you guys could check them...

threestationsquare said...

@Capn Transit, Alon: Here is a corrected version. All lines are well below capacity by this metric (though some are much worse during the 08:00-09:00 narrow peak).

threestationsquare said...

Actually, I added the 08:00-09:00 numbers and even then no line is close to overloaded on average (though some individual trains still will be).

Capn Transit said...

Oh, I see, threestationsquare! I forgot there was more stuff in Appendix II.

Capn Transit said...

Okay, now I made a new chart with the floor space estimates from Table 20. Thanks again!