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| (1649956) | |
MTA Bottleneck Report |
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Posted by Stephen Bauman on Thu Jul 30 07:03:44 2026 The MTA released a "Eliminating Bottlenecks" report. It mainly concerns the merging conflicts and the MTA's plans to eliminate them.They first two projects are Rogers Jct and DeKalb Ave. The report ignores three self-inflicted reasons for the bottlenecks. https://future.mta.info/documents/eliminating-bottlenecks-speeding-up-your-ride.pdf |
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Re: MTA Bottleneck Report |
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Posted by zac on Thu Jul 30 07:26:32 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. What are the three self-inflicted reasons? |
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Re: MTA Bottleneck Report |
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Posted by Q65A on Thu Jul 30 08:45:04 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. Thanks for posting this document, Stephen!I saw it mentioned in a news report yesterday and I wanted to find it. What's interesting and ironic to me is that ideas for alleviating congestion at Rogers Jct. and DeKalb Ave. frequently have been discussed in the internet subway fan communities. |
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(Sponsored) |
iPhone 6 (4.7 Inch) Premium PU Leather Wallet Case - Red w/ Floral Interior - by Notch-It |
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Re: MTA Bottleneck Report |
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Posted by Stephen Bauman on Thu Jul 30 09:08:55 2026, in response to Re: MTA Bottleneck Report, posted by zac on Thu Jul 30 07:26:32 2026. 1. Timetables need 1 second precision. The MTA's timetables have 30 second precision. They are effectively using an hourglass It takes approximately 1 minute for a train to pass through and clear an interlocking.Consider 30 tph (120 second headway) operation. Branch A trains arrive at: 0:00; 4:00; 8:00; etc. Branch B trains arrive at: 2:00; 6:00; 10:00. The merge becomes: 1:00(A); 3:00(B); 5:00(A);7:00(B); etc. Suppose the branch A train is 30 seconds late and the branch B train is 30 seconds early. The arrivals at the interlocking are: 0:30(A) and 1:30(B). The branch A train blocks the interlocking for 1 minute or until 1:30. It does not delay the branch B train. This means that trains must be within 30 seconds of scheduled arrivals to ensure no delays. Determining whether trains are within 30 seconds of their schedule is impossible, when the schedule precision is 30 seconds. The nominal service level capacity is 40 tph, assuming 30 seconds of dwell time at each station. This reduces the on schedule limit to 15 seconds. 2. In order to maintain uniform headways, merges must be balanced. This means both branches must have the same headway. Consider the Rogers Jct: southbound arrivals at Franklin Ave between 6:30 and 7:30 are: #2 @ 8 trains; #3 @ 5 trains; #4 @ 9 trains; #5 @ 9 trains. N.B. the 8 trains for the #2 could be a truncation error. However the #3 @ 5 trains isn't. Suppose all trains operated at 9 tph (400 sec headway). Consider the following schedule for Franklin Ave southbound arrivals. 0(4); 100(3); 200(5); 300(2) 400(4); 500(3); 600(5); 700(2); 800(4); 900(3); 1000(5) The Rogers Jct. merge conflict is between a #3 (New Lots) and a #5 (Flatbush). N.B. there's a 100 second cushion between each each #3 and #5. There's also a 100 second cushion between #2 and # 5 along Nostrand Ave. The downside is that the headways along Nostrand are not uniform. 3. The MTA replaced electro-pneumatic switches with electric ones. This significantly increased actuation time. This is a problem at reversing terminals because the interlocking must handle trains in both directions. This means 15 tph becomes 30 tph and 18 tph becomes 36 tph operation. See what item 1 implies for how trains must adhere to schedules to avoid switching conflicts. Actuation time must be added to the time required to clear the interlocking. This time is also compromised because incoming and outgoing trains are slower. Incoming because of the bumper block; outgoing because of the brake test. |
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Re: MTA Bottleneck Report |
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Posted by irtredbirdr33 on Thu Jul 30 09:55:14 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. Stephen: Thank you for posting this document. The Rogers Junction bottleneck is especially interesting. The logical thing would be to have 7th Avenue trains provide all service on the Nostrand Avenue Line. This would probably be politically untenable as the riders there have always has access to both east and west side services. Larry, Redbirdr33 |
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Re: MTA Bottleneck Report |
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Posted by Stephen Bauman on Thu Jul 30 10:06:45 2026, in response to Re: MTA Bottleneck Report, posted by irtredbirdr33 on Thu Jul 30 09:55:14 2026. The logical thing would be to have 7th Avenue trains provide all service on the Nostrand Avenue Line.That's the recommendation. They would move the exp-to-local switch eastward and make the #5 a local for Nostrand and Kingston, terminating at Utica. |
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Re: MTA Bottleneck Report |
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Posted by Lou from Brooklyn on Thu Jul 30 10:29:58 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. DeKalb: "With new CBTC signals and upgrades to switches, this vital interlocking can be managed more smoothly to avoid delays. "Um how about just not having to stop at a homeball and wait for the Tower Operator to look at a camera image of the rollsign? Simple trust your Train Operators to punch correctly and discipline if they don't. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Thu Jul 30 10:37:06 2026, in response to Re: MTA Bottleneck Report, posted by irtredbirdr33 on Thu Jul 30 09:55:14 2026. There are enough under 40 types living in this area who have been conditioned that they, not the government must be inconvenienced for the good of the city to no longer make that a problem. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Thu Jul 30 10:38:12 2026, in response to Re: MTA Bottleneck Report, posted by Lou from Brooklyn on Thu Jul 30 10:29:58 2026. That also cannot happen until every R68 is retired. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Thu Jul 30 10:39:03 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. They are going to swap the D and Q lines in Brooklyn. They are merely laying the groundwork. |
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Re: MTA Bottleneck Report |
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Posted by Stephen Bauman on Thu Jul 30 12:50:13 2026, in response to Re: MTA Bottleneck Report, posted by Lou from Brooklyn on Thu Jul 30 10:29:58 2026. how about just not having to stop at a homeball and wait for the Tower Operator to look at a camera image of the rollsign?Tower operations should have been automated 50 years ago. London implemented it in the 1950's using a variation of a Jacquard loom and updated them with PDP-8's in the 1960's. The Flushing Line automated Queens bound switching in the 1950's with Identra. The MTA has scheduled merging conflicts at Gold. Southbound the travel time between Canal and Gold and Grand and Gold should be the approximately the same. The schedule for 7/29/2026 calls for B leaving Grand at 17:58:30 and a Q leaving Canal at 17:58:30. This is a standard merge, with both trains scheduled to arrive at the interlocking at the same time. CBTC will not resolve built in merging conflicts. |
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Re: MTA Bottleneck Report |
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Posted by Bill from Maspeth on Thu Jul 30 13:15:07 2026, in response to Re: MTA Bottleneck Report, posted by irtredbirdr33 on Thu Jul 30 09:55:14 2026. There lies the problem. On one side of their mouth Janno Lieber and company proclaim "great customer service" yet if the answer is to send East Side trains to Flatbush and West Side trains to Utica/New Lots so much for "great customer service" due to a transfer at Franklin Ave. For approx. half the ridership.What about all the major 24/7 service changes in order to rebuild Rogers Jct. (and DeKalb)? There is no easy answer here. |
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Re: MTA Bottleneck Report |
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Posted by Bill from Maspeth on Thu Jul 30 13:25:28 2026, in response to Re: MTA Bottleneck Report, posted by Lou from Brooklyn on Thu Jul 30 10:29:58 2026. Many times the train operators punch correctly and get presented with the wrong line-up and take it. Now everybody is in trouble including the dispatcher for not supervising their towermen. This "full stop" rule came about not from downtown but from the individual line superintendents long ago. It would be up to "downtown" to over rule, but they haven't. CBTC will correct this along with the tower operators, much fewer, relocated to the OCC. I am not defending anything here, I'm just telling you how it works. |
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Re: MTA Bottleneck Report |
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Posted by Bill from Maspeth on Thu Jul 30 13:30:15 2026, in response to Re: MTA Bottleneck Report, posted by Chris R16/R2730 on Thu Jul 30 10:39:03 2026. Rearranging the deck chairs on The Titanic again.Poor customer service if all Brighton Trains are Sixth Ave. and 4th Ave. Trains are Broadway. |
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Re: MTA Bottleneck Report |
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Posted by zac on Thu Jul 30 15:14:21 2026, in response to Re: MTA Bottleneck Report, posted by Bill from Maspeth on Thu Jul 30 13:30:15 2026. The other issue with swapping is there is no cross platform transfer. Nobody can convince me that changing trains at Atlantic or taking the slow boat through the tunnel will make anything easier for anybody. It won't matter if we can squeeze a few more trains per hour through if I've got to make a 10 minute transfer. |
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Re: MTA Bottleneck Report |
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Posted by AlM on Thu Jul 30 15:44:57 2026, in response to Re: MTA Bottleneck Report, posted by Chris R16/R2730 on Thu Jul 30 10:39:03 2026. Switching the 2 and 5 just subjects people to a cross-platform transfer. That price may be worth it for quicker service.But switch the D and Q and you're stuck. No easy route from 4th Ave Brooklyn to 6th Ave Manhattan or Brighton Line to Broadway. |
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Re: MTA Bottleneck Report |
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Posted by Wallyhorse on Thu Jul 30 17:28:21 2026, in response to Re: MTA Bottleneck Report, posted by AlM on Thu Jul 30 15:44:57 2026. Solution there if you did swap the (D) and (Q) in Brooklyn would be whichever is local among the (B) and (D) on Brighton stops at DeKalb for a transfer there to the opposite of the Broadway or 6th Avenue lines on the same platform. |
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Re: MTA Bottleneck Report |
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Posted by gbs on Fri Jul 31 00:53:15 2026, in response to Re: MTA Bottleneck Report, posted by Wallyhorse on Thu Jul 30 17:28:21 2026. All Brighton trains have to stop at DeKalb because they have no access to the bypass tracks. Coming from Atlantic Av they approach DeKalb on the newer north track and can take either side of the platform. This has been true since the reconfiguration of the DeKalb switches in the '50s-'60s. For a cross-platform transfer at DeKalb from a 4 Av Express (like the current D or possible Q), the express would have to switch to the local track just north of Pacific St. The express tracks from Pacific lead directly to the bypass. 
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Re: MTA Bottleneck Report |
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Posted by gbs on Fri Jul 31 00:55:46 2026, in response to Re: MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 10:06:45 2026. This sort of thing has happened before, but for less obvious reasons. When the rush-hour B and C were switched between Washington Heights and the Concourse, Washington Heights lost direct 6 Av service, and the Concourse lost direct 8 Av service. Prior to the switch, Washington Heights had A (8 Av) and B (6 Av) service, and the Concourse had C (8 Av) and D (6 Av) service. This was one of the smart IND designs. Today only the Queens Blvd line has both blue and orange lines. Upper Manhattan is all blue and the Concourse is all orange. Even Fulton St (Brooklyn) is all blue, with A and C service. Even the switches at W4 St show that the original design had 6 Av locals continuing down to Spring St and 8 Av locals continuing to Bway-Lafayette, so below W4 each branch would be both blue and orange. Because the switch routing was changed, the south-bound local trains leaving W4 and the north-bound locals approaching W4 have to travel slowly to diverge, rather than go straight through the switches at normal speed. Before the B/C swap: 
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Re: MTA Bottleneck Report |
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Posted by Wallyhorse on Fri Jul 31 09:11:21 2026, in response to Re: MTA Bottleneck Report, posted by gbs on Fri Jul 31 00:53:15 2026. Oh that's right. I forgot about that.If the (N) and (Q) both were express on 4th Avenue, one would need to go to the bridge track that stops at DeKalb or the (Q) joins the (R) as a local between 36th and Atlantic-Barclays. |
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Re: MTA Bottleneck Report |
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Posted by zac on Sat Aug 1 20:56:31 2026, in response to Re: MTA Bottleneck Report, posted by Wallyhorse on Fri Jul 31 09:11:21 2026. And once you've done any of that you've created another bottleneck. If the N goes to the bridge track at Dekalb you now have 3 lines on one track.Deinterlining Dekalb won't work because whichever routes are on 4th Ave won't stop at Dekalb, leaving Brighton riders with no access. Atlantic Ave transfer is not an alternative as that will add 10 minutes to the ride even if you can walk fast. As it is today I never make that transfer on weekends and basically treat as if it doesn't exist. I'd rather just walk outside at my destination since Broadway and 6th Ave aren't that far apart. |
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Re: MTA Bottleneck Report |
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Posted by murray1575 on Sat Aug 1 21:01:00 2026, in response to Re: MTA Bottleneck Report, posted by gbs on Fri Jul 31 00:53:15 2026. It seems to me that this proposal just reverts to some extent the original November 1967 routing where the D ran on the Brighton line and the B ran on the West End line. When the D ran on the Brighton line it always stopped at DeKalb Avenue as the track configuration required it to do. The N skipped DeKalb Avenue during rush hours and used the turnouts just north of Pacific Street (as it was known then) to reach the express tracks on its way to and from DeKalb Avenue so it could stop there during off peak hours. I am not sure how the B operated in the early days post Chrystie as the 57th St. station had not yet opened. |
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Re: MTA Bottleneck Report |
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Posted by zac on Sat Aug 1 23:11:10 2026, in response to Re: MTA Bottleneck Report, posted by Wallyhorse on Fri Jul 31 09:11:21 2026. And once you've done any of that you've created another bottleneck. If the N goes to the bridge track at Dekalb you now have 3 lines on one track.Deinterlining Dekalb won't work because whichever routes are on 4th Ave won't stop at Dekalb, leaving Brighton riders with no access. Atlantic Ave transfer is not an alternative as that will add 10 minutes to the ride even if you can walk fast. As it is today I never make that transfer on weekends and basically treat as if it doesn't exist. I'd rather just walk outside at my destination since Broadway and 6th Ave aren't that far apart. |
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Re: MTA Bottleneck Report |
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Posted by Olog-hai on Sun Aug 2 01:11:27 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. The report ignores three self-inflicted reasons for the bottlenecksSounds like government, all right. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Sun Aug 2 09:21:48 2026, in response to Re: MTA Bottleneck Report, posted by AlM on Thu Jul 30 15:44:57 2026. They don't care about that. They will argue Broadway and 6th Ave are basically the same lines and will tell you to transfer at Herald Square. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Sun Aug 2 09:25:11 2026, in response to Re: MTA Bottleneck Report, posted by zac on Sat Aug 1 20:56:31 2026. This is true, but they don't care about this. They will argue smooth movement thru Dekalb is more important than transfers. They will argue that riders will simply have to get on the proper train in Manhattan. Inconvenience is no longer an impediment to doing things anymore. |
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Re: MTA Bottleneck Report |
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Posted by cortelyounext on Sun Aug 2 10:13:13 2026, in response to MTA Bottleneck Report, posted by Stephen Bauman on Thu Jul 30 07:03:44 2026. Short Article with Embedded Audio Clip |
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Re: MTA Bottleneck Report |
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Posted by AlM on Sun Aug 2 11:08:16 2026, in response to Re: MTA Bottleneck Report, posted by Chris R16/R2730 on Sun Aug 2 09:25:11 2026. But there is inconvenience involved in the merging too. The train takes longer to get you home. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Sun Aug 2 12:31:31 2026, in response to Re: MTA Bottleneck Report, posted by AlM on Sun Aug 2 11:08:16 2026. These are technical and operational problems the MTA should invest in resolving, not avoiding. |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Sun Aug 9 17:12:09 2026, in response to Re: MTA Bottleneck Report, posted by murray1575 on Sat Aug 1 21:01:00 2026. No. What they want to do is route all Broadway trains into Pacific St via the bypass tracks and all 6th Ave trains to Dekalb and Brighton. They would not have to make any switching moves (barring reroutes) anywhere between Murphy/Prospect Park and Manhattan. |
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Re: MTA Bottleneck Report |
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Posted by Zac on Mon Aug 10 11:18:11 2026, in response to Re: MTA Bottleneck Report, posted by Chris R16/R2730 on Sun Aug 9 17:12:09 2026. They did a survey years ago and they determined that Brighton riders wanted broadway. That’s why the Q is the full time service. There would be a lot of complaints if they try to change that. It may be what they want to do but it won’t fly politically. |
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Re: MTA Bottleneck Report |
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Posted by jackson Park B Train on Mon Aug 10 14:37:47 2026, in response to Re: MTA Bottleneck Report, posted by Zac on Mon Aug 10 11:18:11 2026. Serve the market! |
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Re: MTA Bottleneck Report |
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Posted by Chris R16/R2730 on Thu Aug 20 18:00:58 2026, in response to Re: MTA Bottleneck Report, posted by Zac on Mon Aug 10 11:18:11 2026. That was 23 years ago, when politicians actually feared voters. It doesn't matter what we want, they feel free to force whatever they want on you without consequence. They will tout how this will speed up service, get young dumb influencers to sell it on social media and then approve it. |
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Re: MTA Bottleneck Report |
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Posted by Olog-hai on Thu Aug 20 22:04:29 2026, in response to Re: MTA Bottleneck Report, posted by Chris R16/R2730 on Thu Aug 20 18:00:58 2026. Politicians lost the fear of voters way further back than 23 years ago. |
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Re: MTA Bottleneck Report |
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Posted by HANDBRAKE on Sat Aug 22 22:11:42 2026, in response to Re: MTA Bottleneck Report, posted by Lou from Brooklyn on Thu Jul 30 10:29:58 2026. One possible easy fix at DeKalb is to make use of existing Bluetooth BEACON train tracking transmitters installed at every operating train cab. B Division countdown clocks utilize Beacon transmitters that when detected, are tied to NYCT's I-TRAK train dispatch database. I-TRAK tracks all train intervals to include train consist car numbers. Most if not all B Division terminals and master towers track train movements via I-TRAK. A rail car mounted Beacon UHF transmitter will transmit a coded RF signal that identity's the rail car it is associated with. Each 8 or 10 car train has a minimum of four Beacon transmitters all located within operating capable cabs that, when approaching a station, is detected by saucer shaped antennas located at or near station tunnel entrances. Track geometry plays a major role with how soon a Beacon signal can be detected, processed through I-TRAK to identify the interval, and then displayed on an overhead train arrival display. To ensure redundancy to train identification, installing beacon receivers in proximity to tunnel portals at the Brooklyn end of the Manhattan Bridge at a length to capture, at a minimum, the first and the two center operating cabs of a train. This will ensure sufficient redundancy in RF signal identification should the Beacon transmitter in the operating cab not be operational. Once detected, the transmitted Beacon signal is processed through the I-TRAK database, and then the interval is displayed to tower operators using their existing I-TRAK PC’s or via an independent overhead display that will correctly identify an interval for routing through the interlocking plant. The same principle can be applied to northbound trains approaching DeKalb. The use of Beacon with the existing practice of a train operators punch will reduce or eliminate the requirement to first identify all inbound trains from the Manhattan bridge via a tunnel mounted CCTV camera to ensure a correct lineup by the tower. Using the existing Beacon infrastructure, the MTA potentially has in place an interim solution that will help reduce congestion at DeKalb junction until CBTC has been implemented. My familiarity with the Beacon project in late 2016, and during the RTO VHF Radio Narrowband contract, was at what was then known as NYCT CPM, now MTA C&D. Underground station installations were performed by in-house forces. The project lead was MTA IT, and not CPM. Sometimes thinking out of the box helps solve problems. At the MTA the box is very big. |
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