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RR503

Subway Capacity Thread

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Given the uproar from those in the 179 thread, I'm bringing the issue of Williamsburg Bridge capacity over here. I hope for this thread to also get good use in discussions about system capacity generally. There's a lot to say on both the historical and current fronts.  

The offending posts in the other thread begin here

I will be back in the not too distant future with a spreadsheet tabulating maximum historical throughputs on all tracks in the system, as well as current statistics. 

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Just now, RR503 said:

Given the uproar from those in the 179 thread, I'm bringing the issue of Williamsburg Bridge capacity over here. I hope for this thread to also get good use in discussions about system capacity generally. There's a lot to say on both the historical and current fronts.  

The offending posts in the other thread begin here

I will be back in the not too distant future with a spreadsheet tabulating maximum historical throughputs on all tracks in the system, as well as current statistics. 

What was the actual increase in capacity afforded by the new South Ferry terminal?

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6 minutes ago, Union Tpke said:

What was the actual increase in capacity afforded by the new South Ferry terminal?

The new South Ferry terminal was projected to berth about 24 (1) trains there.

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3 minutes ago, Union Tpke said:

What was the actual increase in capacity afforded by the new South Ferry terminal?

Depends on how you define increase. The big issue with the old SF was the need to sit at Rector as you waited for people to walk up, which brought capacity down to the 19tph range. New SF obviates that, so you can run up to 24. That said, you could also just have trusted people to know where to be, and got >>19tph out of old SF. 

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Posted (edited)

Okay, first item for you all. I recently visited the Transit Museum Archives, and photographed a book with annual ridership data for every station (and when I say every, I mean every, as in including closed ones) from 1940 to 1995. I've renamed the images to make an ordered book, and plan to go in tomorrow and make some quick access folders so you don't have to page through the whole thing to find one data point. Given the relevance of ridership to capacity, thought this would be a good way to kick off this thread.

Here is the link:

https://drive.google.com/open?id=1g3pNbvpfqGE4g9v-7t3bfU0xO23U40fp

Enjoy!

Edited by RR503
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8 hours ago, RR503 said:

Depends on how you define increase. The big issue with the old SF was the need to sit at Rector as you waited for people to walk up, which brought capacity down to the 19tph range. New SF obviates that, so you can run up to 24. That said, you could also just have trusted people to know where to be, and got >>19tph out of old SF. 

That is what I thought. Why can't more than 24 be run?

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6 hours ago, Bay Ridge Express said:

1954.gif

Is there a present-day version of this map? I find it really useful to study.

Probably not public.

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Posted (edited)
3 hours ago, Union Tpke said:

That is what I thought. Why can't more than 24 be run?

No tail tracks, and the crossover is set back a bit from the station. It's probably possible to squeeze another 2 or so out with faster turnarounds though...

1 hour ago, Fan Railer said:

Probably not public.

It'd be exceedingly easy to create one, provided you know how to use illustrator. All the tph data is public, and train lengths are common knowledge. I may give it a shot...

Edited by RR503
got my adobe products mixed up
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16 hours ago, RR503 said:

Mind if I use this data for a term paper I'm writing for school about the subway system's downfall in the 70s and 80s? I've been looking for nice ridership data that extends before the 70s as well as after, and this is a holy grail for me with how specific it is! 

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27 minutes ago, Enjineer said:

Mind if I use this data for a term paper I'm writing for school about the subway system's downfall in the 70s and 80s? I've been looking for nice ridership data that extends before the 70s as well as after, and this is a holy grail for me with how specific it is! 

Yes! I should have been clearer — this is for anyone and everyone to use. I included the cover and title pages to aid in citation. If you digitize anything, please do send along. 

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Posted (edited)
21 hours ago, RR503 said:

The offending posts in the other thread begin here.

Offending? Whatever you say. Although I honestly had no idea what happen last night in the R179 Thread that made that individual in question blow off hot steam other than the fact that the Williamsburg Bridge topic was sorta drifty in a way, as I was not active at the time nor was I viewing the forums from offline at the time.

But from what I saw as I logged back on, Lance has already sorted out the problem. So everyone should be cool by now.

Edited by Jemorie

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Posted (edited)
7 minutes ago, Jemorie said:

Offending? Whatever you say. Although I honestly had no idea what happen last night in the R179 Thread that made that individual in question blow off hotstem other than the fact that the Williamsburg Bridge topic was sorta drifty in a way, as I was not active at the time nor was I viewing the forums from offline at the time.

But from what I saw as I logged back on, Lance has already sorted out the problem. So everyone should be cool by now.

'Twas sarcasm. I most certainly was a participant. 

Edit: in other news, I've put all the pages of the old ridership book into their own folders. Hope this is helpful!

Edited by RR503
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Posted (edited)
14 minutes ago, RR503 said:

'Twas sarcasm. I most certainly was a participant. 

Edit: in other news, I've put all the pages of the old ridership book into their own folders. Hope this is helpful!

Oh my bad.

And thanks. I was actually quite glad I at first brought it up in the R179 Thread, as the positive outcome was that it lead to a more interesting/more informative discussion and now we got two separate threads (this one and the WillyB Thread) for it.

Edited by Jemorie
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9 hours ago, RR503 said:

It'd be exceedingly easy to create one, provided you know how to use illustrator. All the tph data is public, and train lengths are common knowledge. I may give it a shot...

Absolutley, I’ll see and try if I can make some maps as well somewhere down the road, though I do have limited time. Inkscape is another good alternative to Adobe Illustrator thats free also which may come in handy. 

Other than that, this is an amazing idea so far, cant wait to see where it goes @RR503. Keep it up!

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On 4/2/2019 at 6:53 PM, RR503 said:

'Twas sarcasm. I most certainly was a participant. 

Edit: in other news, I've put all the pages of the old ridership book into their own folders. Hope this is helpful!

I’m just amazed at the level of analysis you and others put into the data for these discussions.

Even when we don’t agree (ie congestion charge), I’m beyond impressed by how well you and everyone make the data argument versus my “body in the seat” - based argument.

Kudos to you all.

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6 hours ago, Deucey said:

I’m just amazed at the level of analysis you and others put into the data for these discussions.

Even when we don’t agree (ie congestion charge), I’m beyond impressed by how well you and everyone make the data argument versus my “body in the seat” - based argument.

Kudos to you all.

Thank you! I'm glad someone is enjoying my ramblings. 

For whatever its worth, I really enjoy your posts too -- especially on governance. You're extremely well spoken. 

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The full NYMTC data set (which has adequately granular data back to 1973) can be found here — Capn’s sheets seem to just be pulls from those: 

https://www.nymtc.org/Data-and-Modeling/Transportation-Data-and-Statistics/Publications/Hub-Bound-Travel

I’ve compiled peak hour TPH data from every year into a big sheet; ridership and cars are WIP.

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Wanna bring the CBTC discussion over from the R179 thread. @P3F said:

Quote

What I'm thinking, is whether CBTC on the El would allow for any capacity increases at its southern end. If I remember correctly, the  tracks at CI are currently maxed out in terms of capacity, and that's with 20% of trains being turned at Kings Highway. If the issues are mostly at the terminal, then I doubt CBTC will help much. But I believe the slow curves at West 8th Street might also contribute to the low capacity.

 Edit: I'm sorry, I didn't realize this was the R179 thread. This should probably move over to the Subway Capacity thread.

Currently, the split between KH and CI is more like 50/50. You could probably run 10-12 tph out of the Stillwell pockets (the (D)(N)(Q) do it, and I've seen some *really* fast track turnovers on the (F) during the AM rush) with today's signalling; the question I think is more about demand and car availability. Culver CBTC will definitely help increase capacity in the area, but again, do we need more trains?

About CBTC in general: the subway's signal system really varies in age. Fulton, 8th and Crosstown all have ancient (essentially original) signal systems, while areas like CPW/Branches, Culver and BMT south were redone within the last three decades. (If you want to go in depth on this, check out this set of track maps which tracks the layout/history of interlockings, which will give you a general sense for the age of area). While age does not necessarily track with function, it does track with assumptions about train performance (which braking/acceleration rates were used in design) and operator competency (whether or not we provide absolute protection, so assuming full speed through stations and the like), which in turn inform the degree to which the signal system has to be modified to meet current safety standards, and thus capacity. Areas whose design significantly and impactfully deviates from modern assumptions should be those that are targeted for resignalling/CBTC -- fix the bottlenecks, in essence. 

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Posted (edited)
4 hours ago, RR503 said:

Wanna bring the CBTC discussion over from the R179 thread. @P3F said:

Currently, the split between KH and CI is more like 50/50. You could probably run 10-12 tph out of the Stillwell pockets (the (D)(N)(Q) do it, and I've seen some *really* fast track turnovers on the (F) during the AM rush) with today's signalling; the question I think is more about demand and car availability. Culver CBTC will definitely help increase capacity in the area, but again, do we need more trains?

About CBTC in general: the subway's signal system really varies in age. Fulton, 8th and Crosstown all have ancient (essentially original) signal systems, while areas like CPW/Branches, Culver and BMT south were redone within the last three decades. (If you want to go in depth on this, check out this set of track maps which tracks the layout/history of interlockings, which will give you a general sense for the age of area). While age does not necessarily track with function, it does track with assumptions about train performance (which braking/acceleration rates were used in design) and operator competency (whether or not we provide absolute protection, so assuming full speed through stations and the like), which in turn inform the degree to which the signal system has to be modified to meet current safety standards, and thus capacity. Areas whose design significantly and impactfully deviates from modern assumptions should be those that are targeted for resignalling/CBTC -- fix the bottlenecks, in essence. 

The only issue I have (and probably most other commuters have) is that there have been recent delays based on signal failures or problems, even on lines that are not slated to get CBTC soon (if you look at the Unplanned Subway Service Changes forum some recent examples that have been brought up are 4 Av, Jerome Av, and West End)

Edited by Bay Ridge Express

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On 4/8/2019 at 12:31 PM, RR503 said:

I've seen some *really* fast track turnovers on the (F) during the AM rush) with today's signalling; the question I think is more about demand and car availability. Culver CBTC will definitely help increase capacity in the area, but again, do we need more trains?

South Culver Express was the original CBTC test area before it was installed on the L train. South Culver later became the multi vendor (siemens vs thales) VOBC/Wayside interoperability certification area, but I believe that contract was a bust and there has never been interoperability so except for 7, rest of NYCT will be Siemens CBTC. So the ONLY reason South Culver is getting CBTC, leaving a gap with old signals from Jay to Church, is since it was the CBTC test grounds. Not for capacity, not for "old signals", not for reliability. It would simply be changing boards in wayside equipment from pre-spec hardware revisions to current spec.

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Posted (edited)
45 minutes ago, bulk88 said:

South Culver Express was the original CBTC test area before it was installed on the L train. South Culver later became the multi vendor (siemens vs thales) VOBC/Wayside interoperability certification area, but I believe that contract was a bust and there has never been interoperability so except for 7, rest of NYCT will be Siemens CBTC. So the ONLY reason South Culver is getting CBTC, leaving a gap with old signals from Jay to Church, is since it was the CBTC test grounds. Not for capacity, not for "old signals", not for reliability. It would simply be changing boards in wayside equipment from pre-spec hardware revisions to current spec.

They’re completely rebuilding all the interlocking hardware/interlocking confings and I believe doing some basic resignalling (though not full AWS, IINM, as was done for Flushing). This isn’t some simple plug and play job. You’re correct in saying that the fact it was the test track gave it a leg up over other corridors, but signal system age plays a role too. Those things are from ‘54. (I never suggested that it was done to increase capacity, FWIW, merely that that’d be an ancillary benefit).

Edited by RR503

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Posted (edited)
20 hours ago, Bay Ridge Express said:

The only issue I have (and probably most other commuters have) is that there have been recent delays based on signal failures or problems, even on lines that are not slated to get CBTC soon (if you look at the Unplanned Subway Service Changes forum some recent examples that have been brought up are 4 Av, Jerome Av, and West End)

The number of signal related delays actually hasn’t changed all that much over the years, and a delay that stems from a signal malfunction isn’t necessarily just a function of there having been a signal malfunction — the availability of flex capacity and competence in incident response play large roles too. The latter things are very much functions of operation and signal design, and not so much ones of the initial failure. 

Edited by RR503
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