Second Avenue Subway Discussion

[LGA Link N Train]

10 hours ago, CenSin said:

This was what I meant:

Broadway trains can turn using the lower level middle track. There is no interference with any other services. Broadway trains can also go to Queens, and 2 Avenue trains can turn using the lower level middle track. Again there is no interference with any other services.

That's brilliant and I agree with this. Say, what did you and @bobtehpanda use to make this? I'm quite interested to know 

 

[CenSin]

39 minutes ago, LGA Link N train said:

That's brilliant and I agree with this. Say, what did you and @bobtehpanda use to make this? I'm quite interested to know

I use Adobe Illustrator. It’s good for arbitrary drawings. But for the long term, I can see myself writing software specifically for rendering these types of diagrams. There is a lot of boilerplate work that goes into making one of these (at least the ones that I do):

• creating the styles for different kinds of tracks (ramps, lower levels, lower lower levels, etc.)
• creating track segments (switches, curves, platform tracks—which I make exactly 2 inches in length in most of my diagrams whether they are straight or curved, etc.)
• adjusting the distance between tracks to remain consistent—even if not to scale
• coloring the tracks and platforms and adjusting the z-index of every object (so that black lines—or inactive tracks—are covered over by colored lines—the active tracks) when I want to illustrate a specific service pattern

A bit of trigonometry also comes into play for connecting curved line segments. If you haven’t learned it well, do your best there. Calculus comes into play for more realistic renderings—those using track transition curves instead of arcs and Bézier curves, but I don’t use them in Illustrator since the software has no support for such advanced curves.

Edited May 21, 2018 by CenSin

[RR503]

Well they sure do look great! 

I will say, though, that I think your plan builds too much. I’d just connect SAS phase 3 to the current connection provisions and a lower level. Then you don’t have to somehow cut through those load bearing walls in the TBMed segments that exist today — you’re only building out already planned connections.

It also gets Queens direct East Side service (something it doesn’t have) and lets the UES keep full/direct West Side service (something it doesn’t have otherwise). 

[bobtehpanda]

15 hours ago, CenSin said:

Broadway trains can turn using the lower level middle track. There is no interference with any other services. Broadway trains can also go to Queens, and 2 Avenue trains can turn using the lower level middle track. Again there is no interference with any other services.

So I'm looking at the giant current trackmap and it appears there are crossovers both in front of and behind 72 St. So my plan essentially result in three service plans

- SAS

- Bypass

- SAS

 - Bypass

If Bypass tracks are down, terminates at 72 lower and continues to SAS or terminates at upper level.

If SAS tracks are down, terminates at 72 upper and continues to Bypass or terminates at lower level.

Arguably your third track is useful for short turns, but I can't really imagine a scenario where 72 is about as far as you want to send a train given options further down the line.

[CenSin]

1 hour ago, bobtehpanda said:

So I'm looking at the giant current trackmap and it appears there are crossovers both in front of and behind 72 St. So my plan essentially result in three service plans

- SAS

- Bypass

- SAS

 - Bypass

If Bypass tracks are down, terminates at 72 lower and continues to SAS or terminates at upper level.

If SAS tracks are down, terminates at 72 upper and continues to Bypass or terminates at lower level.

Arguably your third track is useful for short turns, but I can't really imagine a scenario where 72 is about as far as you want to send a train given options further down the line.

If the 60 Street tubes are down (and Lexington Avenue/59 Street isn’t always an option to turn back trains), all those trains are going to get rerouted to 2 Avenue. It’s better that some station is there to catch that traffic and turn it around than to force it all the way to 125 Street or Jamaica (via the bypass). I have my doubts that 125 Street can handle all the traffic. Of course, if the bypass connector becomes one of those expendable parts of the system, we may see the MTA shutting down bypass service every time there is an incident to turn 72 Street lower level into a terminal for the extra Broadway or 6 Avenue trains.

5 hours ago, RR503 said:

Well they sure do look great! 

I will say, though, that I think your plan builds too much. I’d just connect SAS phase 3 to the current connection provisions and a lower level. Then you don’t have to somehow cut through those load bearing walls in the TBMed segments that exist today — you’re only building out already planned connections.

It also gets Queens direct East Side service (something it doesn’t have) and lets the UES keep full/direct West Side service (something it doesn’t have otherwise). 

It would probably have been better to build what was originally planned and just leave the lower level as 2 tracks. When making this diagram, I took into consideration the engineering complexity of hollowing out another level and building the ramps to the lower level. One of the considerations was the depth of the tunnel and width of the street above.

[bobtehpanda]

9 hours ago, CenSin said:

If the 60 Street tubes are down (and Lexington Avenue/59 Street isn’t always an option to turn back trains), all those trains are going to get rerouted to 2 Avenue. It’s better that some station is there to catch that traffic and turn it around than to force it all the way to 125 Street or Jamaica (via the bypass). I have my doubts that 125 Street can handle all the traffic. Of course, if the bypass connector becomes one of those expendable parts of the system, we may see the MTA shutting down bypass service every time there is an incident to turn 72 Street lower level into a terminal for the extra Broadway or 6 Avenue trains.

It would be a lot easier to just build local->express switches north of 57 St so that locals can continue onto SAS while expresses terminate at 57. I don't think the marginal benefit of a three-track lower-level is worth the additional cost.

[CenSin]

8 hours ago, bobtehpanda said:

It would be a lot easier to just build local->express switches north of 57 St so that locals can continue onto SAS while expresses terminate at 57.

So regular SAS service from Broadway should be suspended while the trains that don’t usually go there end up picking up the slack…? Trains should be going as close as possible to their original destination and not out of the way in the event of a reroute.

8 hours ago, bobtehpanda said:

I don't think the marginal benefit of a three-track lower-level is worth the additional cost.

That’s the same reasoning that killed the third track in the first iteration of the station.

[Lawrence St]

Why don't we instead build 125th St as an island station without curving onto 125th St and instead build an in-system passageway between 125th St on Lexington and 125th St on SAS? Surely would save the cost a lot.

[CenSin]

26 minutes ago, Lawrence St said:

Why don't we instead build 125th St as an island station without curving onto 125th St and instead build an in-system passageway between 125th St on Lexington and 125th St on SAS? Surely would save the cost a lot.

I had a look at the area… parking lots, poorhouses, auto repair shops all at the foot of a bridge. No way they’re getting a station.

[T to Dyre Avenue]

1 hour ago, Lawrence St said:

Why don't we instead build 125th St as an island station without curving onto 125th St and instead build an in-system passageway between 125th St on Lexington and 125th St on SAS? Surely would save the cost a lot.

Then it would be a useless connection, because it would be too far to walk for  or Metro North riders. I’m much more in favor of building the  platform at 125th closer to the surface, so that it can be a convenient transfer point and not cost more than some countries’ GDPs. The only drawback to building it closer to the surface is that the  (or  in the future) would be unable to go all the way down 125th St. 

1 hour ago, CenSin said:

I had a look at the area… parking lots, poorhouses, auto repair shops all at the foot of a bridge. No way they’re getting a station.

Most of that is on the north side of 125th. If the station platform were to be situated a bit south of 125th (perhaps between 122nd and 125th), then it would be more likely to get decent ridership. You’d then locate the northernmost station entrances on 125th.

[CenSin]

7 minutes ago, T to Dyre Avenue said:

 The only drawback to building it closer to the surface is that the  (or  in the future) would be unable to go all the way down 125th St.

That’s not really much of a drawback. The 2 Avenue Line is supposed to add capacity to interborough transit. A 125 Street crosstown takes some of that away.

[Wallyhorse]

On 5/21/2018 at 2:19 PM, CenSin said:

If the 60 Street tubes are down (and Lexington Avenue/59 Street isn’t always an option to turn back trains), all those trains are going to get rerouted to 2 Avenue. It’s better that some station is there to catch that traffic and turn it around than to force it all the way to 125 Street or Jamaica (via the bypass). I have my doubts that 125 Street can handle all the traffic. Of course, if the bypass connector becomes one of those expendable parts of the system, we may see the MTA shutting down bypass service every time there is an incident to turn 72 Street lower level into a terminal for the extra Broadway or 6 Avenue trains.

It would probably have been better to build what was originally planned and just leave the lower level as 2 tracks. When making this diagram, I took into consideration the engineering complexity of hollowing out another level and building the ramps to the lower level. One of the considerations was the depth of the tunnel and width of the street above.

Another reason why any Queens offshoot of the SAS via 79th I would do would include a three-track stop at York/1st Avenue.  Then you have that AND 72nd to short-turn trains if need be plus giving those in arguably the most densely populated area of the country even more options (and I would not be surprised if by the time such is built you'd have even more high-rises and/or bigger ones than there now).  

[Wallyhorse]

6 hours ago, CenSin said:

That’s not really much of a drawback. The 2 Avenue Line is supposed to add capacity to interborough transit. A 125 Street crosstown takes some of that away.

Yes, but I think having a crosstown on 125 is going to be long-term extremely important since such can include transfers to ALL of the other lines on 125 PLUS the fact by the time any such is built, Columbia will have completed its expansion that I think is going to put heavy pressure on the (1) and Metro-North there (assuming a new 125th Street station on 12th Avenue is built).  That's why I think such is important. 

[CenSin]

2 hours ago, Wallyhorse said:

Another reason why any Queens offshoot of the SAS via 79th I would do would include a three-track stop at York/1st Avenue.  Then you have that AND 72nd to short-turn trains if need be plus giving those in arguably the most densely populated area of the country even more options (and I would not be surprised if by the time such is built you'd have even more high-rises and/or bigger ones than there now).  

Do describe how this would work operationally. A station at 1 Avenue would add no benefit to short-turn operations to the best of my knowledge. How is this improved upon?

On 5/20/2018 at 8:49 PM, CenSin said:

 

[R68OnBroadway]

11 hours ago, CenSin said:

I had a look at the area… parking lots, poorhouses, auto repair shops all at the foot of a bridge. No way they’re getting a station.

Maybe you could move the 125th stop to 125th/3rd instead to allow for a stop at 125th with better access to East Harlem and transfers. From here you could then extend the line under the Harlem River to 3rd-138th on the  and later to Fordham Plaza.

[T to Dyre Avenue]

On 5/22/2018 at 11:13 AM, CenSin said:

That’s not really much of a drawback. The 2 Avenue Line is supposed to add capacity to interborough transit. A 125 Street crosstown takes some of that away.

I fully agree. I would much rather they build the Lex-125th  station with the idea that in the not too far-off future all SAS service in Upper Manhattan will continue north to the Bronx and provide at least two routes from the Bronx to SAS. Something similar to what London Transport did with the Jubilee Line when it terminated at Charing Cross before they extended it to East London in 1999 (it had already been planned to extend Jubilee to East London when the line first opened in 1979).

On 5/22/2018 at 5:39 PM, Wallyhorse said:

Yes, but I think having a crosstown on 125 is going to be long-term extremely important since such can include transfers to ALL of the other lines on 125 PLUS the fact by the time any such is built, Columbia will have completed its expansion that I think is going to put heavy pressure on the and Metro-North there (assuming a new 125th Street station on 12th Avenue is built).  That's why I think such is important. 

But doing “such” forces the Lexington-125th  station into a dual role of SAS station PLUS 125th St crosstown station. There are a number of reasons why that’s not a good thing. First, the platform has to be built deeper to clear both levels of the , Second, you limit service to the Bronx because up to half the SAS capacity has to go to 125th St. Third, that also limits on the 125th crosstown segment. A 125th crosstown should really be its own line, so it’s not limited by merging and reverse branching.

[Wallyhorse]

3 hours ago, T to Dyre Avenue said:

I fully agree. I would much rather they build the Lex-125th  station with the idea that in the not too far-off future all SAS service in Upper Manhattan will continue north to the Bronx and provide at least two routes from the Bronx to SAS. Something similar to what London Transport did with the Jubilee Line when it terminated at Charing Cross before they extended it to East London in 1999 (it had already been planned to extend Jubilee to East London when the line first opened in 1979).

But doing “such” forces the Lexington-125th  station into a dual role of SAS station PLUS 125th St crosstown station. There are a number of reasons why that’s not a good thing. First, the platform has to be built deeper to clear both levels of the , Second, you limit service to the Bronx because up to half the SAS capacity has to go to 125th St. Third, that also limits on the 125th crosstown segment. A 125th crosstown should really be its own line, so it’s not limited by merging and reverse branching.

The way I would do that would be the would go to 125th-Broadway while the continued to The Bronx, possibly running the old 3rd Avenue EL route in The Bronx.

I would also include if possible a connection to the 8th Avenue line at 125/St. Nicholas that mainly would be for G.O.'s but also could be used for an SAS route to either 207 or the Concourse line. 

[bobtehpanda]

On 5/22/2018 at 5:21 AM, CenSin said:

So regular SAS service from Broadway should be suspended while the trains that don’t usually go there end up picking up the slack…? Trains should be going as close as possible to their original destination and not out of the way in the event of a reroute.

That’s the same reasoning that killed the third track in the first iteration of the station.

Getting local Broadway instead of express Broadway is really not the worst thing, especially when the difference in construction difficulty is so large.

You're talking about a backup plan for a scenario that is once in a blue moon with a construction cost difference of hundreds of millions of dollars, if not a billion or two. We have limited, and in the case of the third track in the first iteration it wasn't even a very good solution to a problem; Broadway would still be capped at half capacity, probably less than that.

I actually prefer the third track wasn't built, because the existence of a half-good-enough solution is going to prevent the full, good solution from being built (namely, a separate lower level terminating platform). The third track only made sense if you thought that the current underutilized Broadway setup should be locked in stone.

[RR503]

4 hours ago, bobtehpanda said:

 I actually prefer the third track wasn't built, because the existence of a half-good-enough solution is going to prevent the full, good solution from being built (namely, a separate lower level terminating platform). The third track only made sense if you thought that the current underutilized Broadway setup should be locked in stone.

Exactly. In fact, if SAS is built as per current plans, it actually won't add any Manhattan capacity. By sharing with the , it is limiting Broadway express service to around 15tph, thus making the addition of the  just a redistribution of trunk capacity. If an SAS service is sent to Queens to mitigate the only-15tph-south-of-72 situation (say, replacing the  on QB local) it is preventing the rerouting of the  to 63rd, solidifying the capacity limit on 8th Avenue caused by only one 8th service being able to travel east on 53 -- in other words, another capacity redistribution. 

 

Edited May 27, 2018 by RR503

[CenSin]

12 hours ago, RR503 said:

16 hours ago, bobtehpanda said:

Getting local Broadway instead of express Broadway is really not the worst thing, especially when the difference in construction difficulty is so large.

You're talking about a backup plan for a scenario that is once in a blue moon with a construction cost difference of hundreds of millions of dollars, if not a billion or two. We have limited, and in the case of the third track in the first iteration it wasn't even a very good solution to a problem; Broadway would still be capped at half capacity, probably less than that.

I actually prefer the third track wasn't built, because the existence of a half-good-enough solution is going to prevent the full, good solution from being built (namely, a separate lower level terminating platform). The third track only made sense if you thought that the current underutilized Broadway setup should be locked in stone.

Exactly. In fact, if SAS is built as per current plans, it actually won't add any Manhattan capacity. By sharing with the , it is limiting Broadway express service to around 15tph, thus making the addition of the  just a redistribution of trunk capacity. If an SAS service is sent to Queens to mitigate the only-15tph-south-of-72 situation (say, replacing the  on QB local) it is preventing the rerouting of the  to 63rd, solidifying the capacity limit on 8th Avenue caused by only one 8th service being able to travel east on 53 -- in other words, another capacity redistribution.

Completely segregating 2 Avenue traffic from Broadway traffic is one way to make regular service patterns sane.

16 hours ago, bobtehpanda said:

You're talking about a backup plan for a scenario that is once in a blue moon with a construction

The scenario happens every week practically. There isn’t a month when trains aren’t rerouted to 96 Street—whether it’s planned service changes or emergency reroutes. And it makes sense that 96 Street would get the traffic, because:

• You want to keep reroutes as un-deviant as possible.
• You want to terminate trains closer to their regular route than send them off to some far-flung terminal.
• You want to disturb as little as possible other services that do not run on the disturbed lines.

Not having a short-turn terminal could work, assuming that the regular service patterns change as well (which I support since it creates a clean separation of traffic):

• All Broadway express trains go to Queens via 72 Street lower level
• All 2 Avenue trains continue straight down the corridor

When a problem arises:

• Astoria: trains run to Woodside, terminating at a center track. Those who need service along 31 Street get off at 31 Street–34 Avenue and transfer to a bus. Those who need the Flushing Line transfer at 61 Street–Woodside.
• Queens Boulevard: trains run via the bypass and join the mainline after bypassing the obstruction. The is an alternative to get to Jackson Heights–Roosevelt Avenue by transferring at 61 Street–Woodside.
• Grand Concourse: depending on the state of 2 Avenue, trains run up to 125 Street (providing access to the ) or up 3 Avenue (a distant alternative to Grand Concourse).
• Central Park West: trains run up to 125 Street, and if the line continues across to Broadway, it provides a sort of bridge between two segments of the line cut off by the obstruction; passengers can transfer from train to train, avoiding the bus.

[KK 6 Ave Local]

Just came up with what may be one of my best plans:

Connect the SAS and PATH, making my proposed service pattern this:

Local 1: Gun Hill Rd/Third Av - Jamaica via Atlantic Branch

Local 2: B'way/125 St - Coney Island 

Express 1: (U) Rockaway Park - Newark 

Express 2: (V) LGA - Bayonne

[officiallyliam]

19 minutes ago, KK 6 Ave Local said:

Just came up with what may be one of my best plans:

Connect the SAS and PATH, making my proposed service pattern this:

Local 1: Gun Hill Rd/Third Av - Jamaica via Atlantic Branch

Local 2: B'way/125 St - Coney Island 

Express 1: (U) Rockaway Park - Newark 

Express 2:  LGA - Bayonne

PATH and the B Division of the subway - which SAS is part of - have distinctly incompatible loading gauges; in other words, the sizes of the tunnels and clearances are not the same. Specifically, PATH cars - which are 48' long and 9' wide - are smaller than B Div cars, which are 60' (or 75') long and 10' wide. There's no chance that any B Div subway car is running through PATH tunnels, unless you're proposing a total rebuild of the PATH tunnels. PATH cars can run in the subway, but you'll have a sizable gap between train and platform at B Div stops that will need to be filled. Unless you want to use PATH-size cars on all SAS lines - which will decrease capacity - we'd need gap fillers at every SAS station, which increase expense and dwell time at stations in exchange for a service pattern that I don't think is going to do all that much.

I'm all for PATH integration, though - and PATH theoretically would be compatible with IRT tunnels - but that's a whole other discussion.

 

[Around the Horn]

What they should have done was that PATH/  combination with the 9/11 money... 

[T to Dyre Avenue]

3 hours ago, KK 6 Ave Local said:

Just came up with what may be one of my best plans:

Connect the SAS and PATH, making my proposed service pattern this:

Local 1: Gun Hill Rd/Third Av - Jamaica via Atlantic Branch

Local 2: B'way/125 St - Coney Island 

Express 1: (U) Rockaway Park - Newark 

Express 2:  LGA - Bayonne

That is a good plan. Don’t know how it stacks up against your previous ones, but this one is good.

3 hours ago, officiallyliam said:

PATH and the B Division of the subway - which SAS is part of - have distinctly incompatible loading gauges; in other words, the sizes of the tunnels and clearances are not the same. Specifically, PATH cars - which are 48' long and 9' wide - are smaller than B Div cars, which are 60' (or 75') long and 10' wide. There's no chance that any B Div subway car is running through PATH tunnels, unless you're proposing a total rebuild of the PATH tunnels. PATH cars can run in the subway, but you'll have a sizable gap between train and platform at B Div stops that will need to be filled. Unless you want to use PATH-size cars on all SAS lines - which will decrease capacity - we'd need gap fillers at every SAS station, which increase expense and dwell time at stations in exchange for a service pattern that I don't think is going to do all that much.

I'm all for PATH integration, though - and PATH theoretically would be compatible with IRT tunnels - but that's a whole other discussion.

 

I swear I’ve seen the PATH train cars’ width listed at 9’ 3” and IRT cars at 8’ 10”, so if true, IRT cars would have to displace the PATH fleet if the two were ever to be integrated. 

44 minutes ago, Around the Horn said:

What they should have done was that PATH/  combination with the 9/11 money... 

Agreed. Possibly also a PATH /  combination, if possible (it probably isn’t now). 

[KK 6 Ave Local]

1 hour ago, T to Dyre Avenue said:

 

Agreed. Possibly also a PATH /  combination, if possible (it probably isn’t now). 

Both would work.

Edited June 27, 2018 by KK 6 Ave Local