Second Avenue Subway Discussion

[CenSin]

72nd St Proposals, if there were flying switches

The one in the center looks reasonable enough. I'm not sure about the one on the left. It gives a bit of extra difficulty to the (which would've just gone down a straight tunnel otherwise). Edited September 13, 2014 by CenSin

[realizm]

Well I never got the impression that it was at grade, since Quill made it clear that they are flying junctions to be fair. His proposal looks strikingly similar to the 1968 plan by the MTA tbh.

Edited September 13, 2014 by realizm

[CenSin]

The old documents are still up on the MTA site:

http://web.mta.info/capital/sas_docs/feis/figure2-04.pdf

http://web.mta.info/capital/sas_docs/feis/figure2-05.pdf

Edited September 13, 2014 by CenSin

[realizm]

Yup, thats it. Good research on your part btw!

[MTA Dude]

72nd St Proposals, if there were flying switches

 

Eh, don't look reasonable enough to me. And can you teach me how to add these photos?

[Quill Depot]

The one in the center looks reasonable enough. I'm not sure about the one on the left. It gives a bit of extra difficulty to the (which would've just gone down a straight tunnel otherwise).

 

More simplified and streamlined version. 72nd can also be used as a terminal for all ways. Downtown trains relay after the station

[realizm]

Ok I get it. I think what CenSin means is that the radial curves are too sharp for appropriate clearance. Looks good to me though.

[Quill Depot]

Eh, don't look reasonable enough to me. And can you teach me how to add these photos?

 

Press the little IMG button and paste a direct link to the photo. You can also use the 

[img=link to picture here]

Ok I get it. I think what CenSin means is that the radial curves are too sharp for appropriate clearance. Looks good to me though.

Nothing there is to scale, not the curves either. They will probably be father from the station, and with more of a curve.

[realizm]

Nothing there is to scale, not the curves either. They will probably be father from the station, and with more of a curve.

Which is true. Much of what the MTA publishes is not drawn to scale either unless they are literal track maps, even then not exactly drawn to scale.

[RollOver]

@QuillDepot/jimmy7train

 

Did you made these track maps? Please teach me how to someday, because I would LOVE to do these too.

[CenSin]

Ok I get it. I think what CenSin means is that the radial curves are too sharp for appropriate clearance. Looks good to me though.

Actually, what I meant to say was…

 

 

72nd St Proposals, if there were flying switches

Left Diagram

Not sure what's going on here. There seems to be a lot of superfluous switches not serving a clear purpose. The should also not be taking a diverging switch north of 72 Street as it is the principal (main) route along 2 Avenue.

 

(And although not obvious in the center diagram, it's is actually the that takes the diverging path to get to/from the center tracks at 72 Street since the tunnels going north are about 30-feet apart. The switches would take the tracks 10 feet away from each of the tracks towards the center.)

 

Center Diagram

It's the best design yet as either or trains can short turn there. Furthermore, the northbound center track can also be used to orchestrate merges between updown and trains.

 

Right Diagram

Very simple, much like the current plan for 72 Street. But what would the switch from the downtown track to uptown track (where the wye is) be for?

 

 

More simplified and streamlined version. 72nd can also be used as a terminal for all ways. Downtown trains relay after the station

There's one flaw still: there are two distinct tracks for short turning each route. When the respective tracks are used for short turning, all southbound traffic is blocked for the respective route. A using the leftmost track to short turn would have southbound service from above 72 Street suspended until the turning could clear the station. The same goes for the .

[CenSin]

Which is true. Much of what the MTA publishes is not drawn to scale either unless they are literal track maps, even then not exactly drawn to scale.

Take a look at any of the tracks exposed to the all-seeing Google Maps satellite. If the planners had to draw diagrams to scale, there would be very large diagrams with long lines and smaller features just a few pixels when zoomed out. It's not conductive to presentation when you have to use huge prints or make everyone squint to see what really matters.

[realizm]

Take a look at any of the tracks exposed to the all-seeing Google Maps satellite. If the planners had to draw diagrams to scale, there would be very large diagrams with long lines and smaller features just a few pixels when zoomed out. It's not conductive to presentation when you have to use huge prints or make everyone squint to see what really matters.

Indeed it would be a challenge to graphic designers to get it to scale pixel for pixel.

[Quill Depot]

@QuillDepot/jimmy7train

 

Did you made these track maps? Please teach me how to someday, because I would LOVE to do these too.

 

I opened up Paint and used the line tool for tracks, and the box tool for stations.

 

Actually, what I meant to say was…

 

Left Diagram

Not sure what's going on here. There seems to be a lot of superfluous switches not serving a clear purpose. The should also not be taking a diverging switch north of 72 Street as it is the principal (main) route along 2 Avenue.

 

(And although not obvious in the center diagram, it's is actually the that takes the diverging path to get to/from the center tracks at 72 Street since the tunnels going north are about 30-feet apart. The switches would take the tracks 10 feet away from each of the tracks towards the center.)

 

Center Diagram

It's the best design yet as either or trains can short turn there. Furthermore, the northbound center track can also be used to orchestrate merges between updown and trains.

 

Right Diagram

Very simple, much like the current plan for 72 Street. But what would the switch from the downtown track to uptown track (where the wye is) be for?

 

There's one flaw still: there are two distinct tracks for short turning each route. When the respective tracks are used for short turning, all southbound traffic is blocked for the respective route. A using the leftmost track to short turn would have southbound service from above 72 Street suspended until the turning could clear the station. The same goes for the .

 

It was never meant for short-turning Q trains, more of a terminal in case of any problem further up the trackage. The crossover south of the station on the Q southbound. 2 tracks can be used as a terminal for the (middle and left) and 3 for the (all three)

 

[CenSin]

It was never meant for short-turning Q trains, more of a terminal in case of any problem further up the trackage. The crossover south of the station on the Q southbound. 2 tracks can be used as a terminal for the (middle and left) and 3 for the (all three)

 

I'm going to "normalize" all of the existing designs and give a comparison between them. The tracks have been labeled and so have the switches if they need to be referenced.

 

 

This is the current design being built by the MTA:

 

It has 2 switches and the station has 2 tracks without any possibility for short turns. If a signal failure, train failure, or any incident occurs on either track 1 or 2, the entire length of track (up to the nearest switch for turning back trains) is out of service. The MTA could single-track or resort to shuttle buses, but you know how much of a pain in the ass that will be.

 

 

This is the old design proposed by the MTA juxtaposed to yours:

 

MTA Old Design

• Number of switches: 12
• Turns back any train from any direction on track 3 using the switches north or south of it.
• Can orchestrate merges between the and using tracks 1 and 3 at the station.
• Can hold non-revenue trains and malfunctioning revenue trains on track 3 while merging northbound trains into track 1 via switch E instead of A.

Your Design

• Number of switches: 14
• Acts as the northernmost terminal in case of problems north of 72 Street.
• Can turn back northbound trains on tracks 2 and Q2.
• Can turn back northbound trains on any track.
• Can turn back any southbound train approaching 72 Street on track 2.

If it's not already obvious what the problems are, your design:

• does not allow northbound and trains to exchange passengers before merging north of 72 Street.
• has more switches than necessary.
• needs a much longer cavern to be excavated for all the switches (over twice as long).
• has a superfluous track for southbound trains; if trains are approaching southbound in quick succession, only one track will be in use at any time alternating between track 2 and Q2. Meanwhile, northbound and trains arriving at the junction simultaneously must be held on track Q1 (before switch J) and T1 (before switch H) respectively. Northbound trains cannot use track 2 (the center track) because that's the southbound track.
• can only be used to regularly short turn southbound trains north of 72 Street.

The one in the middle was fine:

 

 

[Quill Depot]

The one you have makes the most sense. Thanks. I was trying to find something creative.

[Wallyhorse]

This is the current design being built by the MTA:

It has 2 switches and the station has 2 tracks without any possibility for short turns. If a signal failure, train failure, or any incident occurs on either track 1 or 2, the entire length of track (up to the nearest switch for turning back trains) is out of service. The MTA could single-track or resort to shuttle buses, but you know how much of a pain in the ass that will be.

 

 

This is the old design proposed by the MTA juxtaposed to yours:

 

MTA Old Design

• Number of switches: 12
• Turns back any train from any direction on track 3 using the switches north or south of it.
• Can orchestrate merges between the and using tracks 1 and 3 at the station.
• Can hold non-revenue trains and malfunctioning revenue trains on track 3 while merging northbound trains into track 1 via switch E instead of A.

Your Design

• Number of switches: 14
• Acts as the northernmost terminal in case of problems north of 72 Street.
• Can turn back northbound trains on tracks 2 and Q2.
• Can turn back northbound trains on any track.
• Can turn back any southbound train approaching 72 Street on track 2.

If it's not already obvious what the problems are, your design:

• does not allow northbound and trains to exchange passengers before merging north of 72 Street.
• has more switches than necessary.
• needs a much longer cavern to be excavated for all the switches (over twice as long).
• has a superfluous track for southbound trains; if trains are approaching southbound in quick succession, only one track will be in use at any time alternating between track 2 and Q2. Meanwhile, northbound and trains arriving at the junction simultaneously must be held on track Q1 (before switch J) and T1 (before switch H) respectively. Northbound trains cannot use track 2 (the center track) because that's the southbound track.
• can only be used to regularly short turn southbound trains north of 72 Street.

The one in the middle was fine:

 

 

 

Agree on the one in the middle.  That seems to be the best option.

 

What they should have done was allow for switches both north and south of 72nd in case of an unforseen emergency on either side given how important that station is going to be..

 

 

[realizm]

Agree on the one in the middle.  That seems to be the best option.

 

What they should have done was allow for switches both north and south of 72nd in case of an unforseen emergency on either side given how important that station is going to be..

I agree on the first point, but on the second, overkill. We will have tail tracks as it is with the completion of phase 1 so it may not be necessary for turnarounds. Derailments should be rare since it will not be decades old say like Queens Blvd.

[Quill Depot]

Yeah that's why we're bargaining for a 2 platform station. I agree on the center one now. Would 3 track SAS be possible?

[bobtehpanda]

Yeah that's why we're bargaining for a 2 platform station. I agree on the center one now. Would 3 track SAS be possible?

 

There wouldn't be a point; Phases I and II are designed for two tracks only (more so, since the original 1970s plan was also a two track subway and the Phase II tunnels exist.) An express just below 60th St wouldn't make much sense since you'd be skipping two to four stops max, and wouldn't really provide any meaningful boost to capacity. Plus, the current two tracks is fine for any foreseeable expansions; it can accommodate one line in the Bronx, one line across 125th, one in Queens, and two in Brooklyn, which is probably as much as we're going to build for the next century.

[Quill Depot]

There wouldn't be a point; Phases I and II are designed for two tracks only (more so, since the original 1970s plan was also a two track subway and the Phase II tunnels exist.) An express just below 60th St wouldn't make much sense since you'd be skipping two to four stops max, and wouldn't really provide any meaningful boost to capacity. Plus, the current two tracks is fine for any foreseeable expansions; it can accommodate one line in the Bronx, one line across 125th, one in Queens, and two in Brooklyn, which is probably as much as we're going to build for the next century.

 

I understand. Based on pictures of SAS the tunnels look huge, enough for even two layers of tracks. I figure with CBTC lines can handle about 10 more TPH eventually, so the express tracks will probably not even be needed. 

[leo2car]

No third track: http://secondavenuesagas.com/2008/06/25/rising-costs-shelve-third-second-ave-subway-track-at-72nd/

[realizm]

Yeah we know, were all aware of that article. Actually its just a hypothesis we are making here, basically comparing the 1968 MTA Plan For Action proposals with the current plan from the blueprints in effect from 2007. Its only because of rising costs (as the Second Avenue Sagas article brings out) that that three track plan was shelved, as we all concluded yesterday.

[MTA Dude]

Express SAS is not needed, only for backup between 34th and Hanover, and 96th to 125th. SAS express would skip very few stops.

Press the little IMG button and paste a direct link to the photo. You can also use the 

[img=link to picture here]

 

Nope, too complicated. I wanna upload directly from paint.

[Kamen Rider]

Can't, you need something to host it. Unless you own a server, the moment you shut off the machine, the information wouldn't be accessible. Basically we would only be able to see anything you post while your PC is on and connected to the net.

 

 

Also, I don't get this issue about switches. I live near the Myrtle Ave el. And that has no switches between Myrtle and Metro. Train gets stuck, train gets stuck.

Edited September 15, 2014 by Kamen Rider