Why does split service on the (A) work but won't on other lines?

[Lawrence St]

Don't the  and merge at 50th St or is there another pattern?

[NewFlyer 230]

1 hour ago, Lawrence St said:

Don't the  and merge at 50th St or is there another pattern?

Yes they merge past 50th because at 50th Street the  and  are on separate levels.

[biGC323232]

On 5/13/2018 at 12:57 AM, Daniel The Cool said:

To be fair though, the  from Bedford Park Blvd to Rockaway Park was longer than the  From Jamaica-179th Street to the Rockaways.

Thanks for the info...

[N6 Limited]

On 5/13/2018 at 3:07 PM, Union Tpke said:

The merge at Canal is the main problem.

Yes, the interlocking is slow.  You'll have southbound  trains held outside the station, while the  has already completely crossed over to the express tracks, etc.

[CenSin]

18 minutes ago, N6 Limited said:

Yes, the interlocking is slow.  You'll have southbound  trains held outside the station, while the  has already completely crossed over to the express tracks, etc.

Was this an issue when the IND system was freshly built? It seems very unlike the IND to create problems like this. The IND manifesto was basically to build tracks that could be flexible and support high-speed operation. They learned from the failings of the IRT and BMT.

[N6 Limited]

3 minutes ago, CenSin said:

Was this an issue when the IND system was freshly built? It seems very unlike the IND to create problems like this. The IND manifesto was basically to build tracks that could be flexible and support high-speed operation. They learned from the failings of the IRT and BMT.

I made a post a while back complaining about Canal Street IND, and someone replied to my post saying that the interlocking is new.

[officiallyliam]

8 minutes ago, CenSin said:

Was this an issue when the IND system was freshly built? It seems very unlike the IND to create problems like this. The IND manifesto was basically to build tracks that could be flexible and support high-speed operation. They learned from the failings of the IRT and BMT.

Remember, though, that under the IND's ideal plan, those switches would never be used. The expresses would have gone to Brooklyn; the locals would have gone to World Trade Center only. It's incredibly shortsighted planning, and while the IND designed a lot of very well-executed junctions and higher-speed lines than the IRT or BMT, there were also a ton of really shortsighted and silly planning decisions made: the only-intraborough local trains; the lack of good transfers to IRT and BMT lines, most clearly seen on the ; and heavy reliance on interlining, especially Queens Blvd and Fulton Street, are a few examples of this.

[checkmatechamp13]

On 5/13/2018 at 12:57 AM, Daniel The Cool said:

To be fair though, the  from Bedford Park Blvd to Rockaway Park was longer than the  From Jamaica-179th Street to the Rockaways.

Also the was all-local wheras the is express in Queens.

On 5/13/2018 at 12:21 AM, Deucey said:

If they built the system so trains could terminate and reverse in Midtown I'd be all for eliminating three-borough routes. Ex:  207th to WTC,  168th to West 4th,  to Rockaway Express,  to Lefferts Local - just because long routes have more delays.

It's why I'm not big on LA's Regional Connector since now the Blue Line will be ~40 miles from Long Beach to Azusa and delay-prone because of switching with Expo/Gold Lines twice and the Pasadena slow zone.

But NYCBOT/  didn't build the option to do that here. Since it wasn't, and straphangers want minimal transfers, I'd rather  made the system work and install flexibility wherever it can with speed being higher in importance than present.

So more flying junctions to interline - especially with SAS. Like building ramps to connect to Culver so  can have a second service to LIC in case stuff happens at the West 4th choke point (like the track fire in Jan/Feb 2015 that shut down the entire IND).

 

The issue is that you would end up with a lot of overlap if you tried to terminate services from the south in Midtown while terminating services from the north Downtown. And if you pick one or the otherel you force a lot of transfers.

[Deucey]

1 hour ago, checkmatechamp13 said:

Also the was all-local wheras the is express in Queens.

The issue is that you would end up with a lot of overlap if you tried to terminate services from the south in Midtown while terminating services from the north Downtown. And if you pick one or the otherel you force a lot of transfers.

Mos def it'd be a passenger convenience nightmare having to transfer 3x if you start off along Fulton or the BMT in South Brooklyn headed towards the Grand Concourse, but operationally you'd probably have more reliable service headways and possibly higher costs.

[CenSin]

1 hour ago, checkmatechamp13 said:

The issue is that you would end up with a lot of overlap if you tried to terminate services from the south in Midtown while terminating services from the north Downtown. And if you pick one or the otherel you force a lot of transfers.

That’s the point. The effect of this is to keep service levels high in the central business district while the outer fringes aren’t over served.

A system like this could allow service to be fine-tuned. Today, Sea Beach, Culver and Brighton lines all get more service than what they would warrant alone based on service demands at the other end of their respective flagship routes (Astoria, Queens Boulevard, 2 Avenue). Having routes be two-boroughs long would serve to cut delay factors down, enable flexible service adjustment, and save money.

Of course, the terminals would have to be designed for this kind of scenario.

[bobtehpanda]

1 hour ago, CenSin said:

That’s the point. The effect of this is to keep service levels high in the central business district while the outer fringes aren’t over served.

A system like this could allow service to be fine-tuned. Today, Sea Beach, Culver and Brighton lines all get more service than what they would warrant alone based on service demands at the other end of their respective flagship routes (Astoria, Queens Boulevard, 2 Avenue). Having routes be two-boroughs long would serve to cut delay factors down, enable flexible service adjustment, and save money.

Of course, the terminals would have to be designed for this kind of scenario.

The issue is that many outer borough branches now could feasibly hold their own in terms of ridership. Trains may not be SRO coming out of Brooklyn or Inwood now, but if trains start showing up at 125th St SRO because of the reduced capacity then you've increased platform dwells and the like.

There is a reason why strict suburb-CBD networks have been falling out of favor across Europe and Asia.

[CenSin]

7 hours ago, bobtehpanda said:

The issue is that many outer borough branches now could feasibly hold their own in terms of ridership. Trains may not be SRO coming out of Brooklyn or Inwood now, but if trains start showing up at 125th St SRO because of the reduced capacity then you've increased platform dwells and the like.

There is a reason why strict suburb-CBD networks have been falling out of favor across Europe and Asia.

Well, I don’t expect it to be some final proposal, but that’s the idea. I’ve had various versions ending the routes outside of the central business district as well: Inwood/Downtown Brooklyn + Harlem/Ozone Park + Columbus Circle/Far Rockaway. There isn’t even a clear idea where express and local service should start, and the existing track designs won’t support such a system.

But clearly, the long 32-mile runs are not very reliable.

[bobtehpanda]

8 hours ago, CenSin said:

Well, I don’t expect it to be some final proposal, but that’s the idea. I’ve had various versions ending the routes outside of the central business district as well: Inwood/Downtown Brooklyn + Harlem/Ozone Park + Columbus Circle/Far Rockaway. There isn’t even a clear idea where express and local service should start, and the existing track designs won’t support such a system.

But clearly, the long 32-mile runs are not very reliable.

Are they unreliable because of the length or because of the crazy merging we require? The Eighth Avenue lines have many merges, much more than they need to:

North of CPW

South of CPW

South of 50 St  

Canal

Hoyt

If you were to run all expresses uptown via CPW express and all locals to Queens, you probably would not see nearly any issues. Canal St in particular is way too hairy and causes frequent issues between the , and  ; merging so close to a terminal is just not a good idea.

It's important to separate out what length actually does: length limits the scope of unreliability cascading, but does nothing about the actual unreliable points in the system, namely Canal St.

[CenSin]

3 hours ago, bobtehpanda said:

Are they unreliable because of the length or because of the crazy merging we require? The Eighth Avenue lines have many merges, much more than they need to:

North of CPW

South of CPW

South of 50 St  

Canal

Hoyt

If you were to run all expresses uptown via CPW express and all locals to Queens, you probably would not see nearly any issues. Canal St in particular is way too hairy and causes frequent issues between the , and  ; merging so close to a terminal is just not a good idea.

It's important to separate out what length actually does: length limits the scope of unreliability cascading, but does nothing about the actual unreliable points in the system, namely Canal St.

It could also be both. Mind you, variations in human performance (the train operator and conductor) and passenger movement are accumulated at every station and for every mile driven. Merges are not the only source of problems. Every stop is also a potential incident minor or major. Merges are a major factor, but certainly not the only factor.