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Mysterious2train

4th Av Switch Back In Business

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This weekend, because of the (Q) train not running to Manhattan, (N) trains were stopping at Dekalb Av. Usually when this happens, the (N) just runs local between Atlantic Av-Pacific St and 59th St, but not this time. Yeah, the (N) I was on actually used the infamous switch between Dekalb Av and Pacific St to get to the express track.

 

It was pretty unexpected. The TA's been straying away from using that switch, why start using it now?

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Guest lance25

I guess they don't want the (N) running local in Brooklyn simply because it has to stop at DeKalb anymore.

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This weekend, because of the (Q) train not running to Manhattan, (N) trains were stopping at Dekalb Av. Usually when this happens, the (N) just runs local between Atlantic Av-Pacific St and 59th St, but not this time. Yeah, the (N) I was on actually used the infamous switch between Dekalb Av and Pacific St to get to the express track.

 

It was pretty unexpected. The TA's been straying away from using that switch, why start using it now?

When the pre-2004 (W) ran, the (N) would use that switch to run express after Dekalb. I can't see why they want to avoid it. Not saying they need to use that switch, but it would be nice if the (D) stopped at Dekalb on weekends.

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I've seen this happen pretty common now, once in a while, in the morning rush, when i head to school, (D) and (N) stop at DeKalb and picks up passengers, then heads down 4 Av then switch back to the EXP. i don't know why they don't use the regular EXP track at Dekalb. my guess is delay on (R) service. this happens like once every two weeks.

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That switch has wheel detectors on it, and TA doesn't like to run regular service over switches that have wheel detectors on it. A noted exception: the (J) at Chambers n/b, but then again those clear quick coming into the station, one really has to try to get those to trip you.

 

There have been locations where wheel detectors were installed and then taken out (the most noted one of those is 14st-Union Sq on 2 track, right at the site of the Robert Ray incident that got them installed in the first place. Now the signals still remain and are lit from time to time, but now to cross over that same switch, a call-on must be established once train is in approach to that home signal.). The other major place they were removed was at Canal St - IND. Trains were tripping as slow as 3 MPH (and T/O's at first incorrectly being written up). The other major place they still exist is just before West 4th, which is the reason most trains are crossed over at the high speed switch just south of 42-Bryant Park.

 

Hope the info helps.

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That switch has wheel detectors on it, and TA doesn't like to run regular service over switches that have wheel detectors on it. A noted exception: the (J) at Chambers n/b, but then again those clear quick coming into the station, one really has to try to get those to trip you.

 

There have been locations where wheel detectors were installed and then taken out (the most noted one of those is 14st-Union Sq on 2 track, right at the site of the Robert Ray incident that got them installed in the first place. Now the signals still remain and are lit from time to time, but now to cross over that same switch, a call-on must be established once train is in approach to that home signal.). The other major place they were removed was at Canal St - IND. Trains were tripping as slow as 3 MPH (and T/O's at first incorrectly being written up). The other major place they still exist is just before West 4th, which is the reason most trains are crossed over at the high speed switch just south of 42-Bryant Park.

 

Hope the info helps.

 

Doesn't the switch at Parkchester from the express to the local track northbound also have wheel detectors?

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Doesn't the switch at Parkchester from the express to the local track northbound also have wheel detectors?

 

I wasn't trying to state every location throughout the system that have them, but yes Parkchester has them in both directions entering/leaving the express track (and at Hunts Point for that matter going from middle to outside tracks), but the ones at Parkchester do not work in either direction, it reverted to a regular GT15 and a 15mph switch. I mentioned the (J) line at Chambers as its the place where the official wheel detector video is taken (its not even the only place along the (J) line that have them, either). West 4th was given as an example as many people on here have banged their head about why that switch isn't used more often (allowing a train to go "express", the TA deferring to 42nd instead...

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That switch has wheel detectors on it, and TA doesn't like to run regular service over switches that have wheel detectors on it.

 

Why does the T/A install wheel detectors on switches, then, if it reduces service flexibility and thus reliability/convenience?

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It was a knee jerk reaction (like many other TA rections to events) to the 1993 incident to proliferate the system with them. They never worked right (much like almost all TA invested equipment) and TA eventually gave up on new installations and decomissioned some of the faulty ones (like Canal St and Parkchester). Eventually, tightly strung together (i mean close) groups of GT one shot timers, seen from place to place around the system, has done a better job regulating speed than the wheel detectors. The ones that have worked fairly well however, do remain.

 

It does remain, that using the 20mph switch that has no associated timers at 42nd-Bryant Pk is faster than having a train go down that "express" only to be under wheel detectors gradually slowing the train down to go over a 15mph switch on which a T/O dare better not go over 10. The way around this is having the approach home signal at danger (actual home signal clear) with a straight lineup, only giving the switch once the train has come up to it (still detectors will be on once the switch reverses). Still have to basically stop. Hitting a wheel detector is basically an automatic write-up, and you WILL get days out of it. Its basically two write ups in one (overspeed on a switch, collision with a stop arm). OUCH.

 

In the end, TA concluded that wheel detectors will not be a part of regular service (the noted exception being the (J) at Chambers, but even then its hard to hit those unless one is not making a station stop at Chambers).

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Another way of putting it, they had to "take steps to address the problem" in the aftermath of the wreck. So they came up with this new system (basically, "zero shot timer"), and apparently it wasn't really as efficient as it seemed.

(I too was surprised, last year, when I went over Canal St. for the first time since the new signals were installed, and it took a couple of minutes to realize what was missing).

 

As I've always said, the WD on that switch at Pacific southbound was so excruciatingly slow (you were only safe under 5, basically, and even the people on the platform grew impatient waiting for you to crawl all the way in at a calm walking pace), that they realized it didn't make sense to run regular service over it. However, occasional reroutes or off-hour G.O.s. are OK.

I once suggested them moving the switch to where it could be less sharp of a move (it's on a curve), but that would actually require a lot of modification of the tunnel structure.

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Another way of putting it, they had to "take steps to address the problem" in the aftermath of the wreck. So they came up with this new system (basically, "zero shot timer"), and apparently it wasn't really as efficient as it seemed.

(I too was surprised, last year, when I went over Canal St. for the first time since the new signals were installed, and it took a couple of minutes to realize what was missing).

 

As I've always said, the WD on that switch at Pacific southbound was so excruciatingly slow (you were only safe under 5, basically, and even the people on the platform grew impatient waiting for you to crawl all the way in at a calm walking pace), that they realized it didn't make sense to run regular service over it. However, occasional reroutes or off-hour G.O.s. are OK.

I once suggested them moving the switch to where it could be less sharp of a move (it's on a curve), but that would actually require a lot of modification of the tunnel structure.

Could it be moved south of the station? If I'm correct, there's a segment between Union Street and Pacific Street where there are no vertical support beams between the local and express tracks. I've observed this for the northbound side of the tunnel, but I'm not sure if it's the same for the southbound side. It might have been there as a provision for installing another switch.

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When the pre-2004 (W) ran, the (N) would use that switch to run express after Dekalb. I can't see why they want to avoid it. Not saying they need to use that switch, but it would be nice if the (D) stopped at Dekalb on weekends.

 

I rather like that the (D) skips Dekalb. But as slowly as it passes by the station it may as well actually stop there and pick up passengers.

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I rather like that the (D) skips Dekalb. But as slowly as it passes by the station it may as well actually stop there and pick up passengers.

 

What really would be ideal (from a passengers standpoint) is an island platform between both bypass tracks so trains actually could stop at Dekalb in the bypass (which it wouldn't be a bypass anymore lol), but obviously that's impossible.

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What really would be ideal (from a passengers standpoint) is an island platform between both bypass tracks so trains actually could stop at Dekalb in the bypass (which it wouldn't be a bypass anymore lol), but obviously that's impossible.

They could lower the bypass tracks to a deeper level and have side platforms right underneath the existing island platforms. People would have to take a flight of stairs or elevator (if disabled), but there would be a short transfer between the (B), (D), (N), (Q), and (R).

 

But if there are things underneath the station already (and I don't know what tunnels go through that area), it'd really be impossible.

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What really would be ideal (from a passengers standpoint) is an island platform between both bypass tracks so trains actually could stop at Dekalb in the bypass (which it wouldn't be a bypass anymore lol), but obviously that's impossible.

 

Well while we're on the subject of impossible... close DeKalb to pull off your Robert Moses-like project right after rerouting all tracks from Manhattan Bridge onto elevated structure with a heart-in-your-throat downgrade into Atlantic Ave with single-shot timers all the way there!

 

Awesome! :eek:

 

...how the trains get back to Manhattan? Those tracks go over the bridge! :deadhorse:

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Well while we're on the subject of impossible... close DeKalb to pull off your Robert Moses-like project right after rerouting all tracks from Manhattan Bridge onto elevated structure with a heart-in-your-throat downgrade into Atlantic Ave with single-shot timers all the way there!

 

Awesome! :eek:

 

...how the trains get back to Manhattan? Those tracks go over the bridge! :deadhorse:

 

Or lunar white GT50's in the 60th tube... oh baby!

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