Timers

[Jcb]

What are the worst/slowest lines in the system in terms of timed areas/timer speeds?

[S78 via Hylan]

Most of the 8 Avenue Line.

[SubwayGuy]

Most of the 8 Avenue Line.

 

Huh? Not at all.

 

Lower Broadway and Brooklyn Heights BMT come to mind...Feels like you're always following a train, even when you're not.

[bstar1]

Along the line

[BronxBombers]

Huh? Not at all.

 

Lower Broadway and Brooklyn Heights BMT come to mind...Feels like you're always following a train, even when you're not.

 

If your traveling northbound on the from 14th until 59th it is basically running at slower speed.

[bstar1]

And passing 135 St on exp track .

[trainfan22]

I always found the & line dreadful between Chambers and Nevins street southbound....

 

 

Also the runs over the WillyB & Manhattan Bridges southbound, its sucks riding those routes N/B as well but S/B seems worst.

[Union Tpke]

What percentage of timers would you say are unnecessary?

[SubwayGuy]

If your traveling northbound on the from 14th until 59th it is basically running at slower speed.

 

Between 14th and 34th, you have a handful of timers to protect the 30th street spur switch. Once the train is clear of the switch, it can run at normal speed, but it is going uphill.

 

South of 59th St., signals are required to protect the switch coming from 6th Avenue merging onto the express track. The timers ensure an A train doesn't develop excessive speed coming down the hill and risk a collision.

 

Other than those 2 areas there are really only a couple of other timers on that entire stretch, and that's inclusive of all 4 tracks.

[nightmare402]

Broadway junction on the North and South Express track

[Jsunflyguy]

The S curve on the Broadway El, Cypress Hills I think.

[Brooklyn]

The S curve on the Broadway El, Cypress Hills I think.

 

Trains need to go slow there...even I'll concede THAT.

 

But for some reason I think they put a timer BEFORE trains enter Cypress Hills station--that never used to be there.

[Jsunflyguy]

The OP didnt qualify that the segment be NEEDLESSLY slow. Otherwise nearly all of lower Manhattan should be removed from discussion.

[S78 via Hylan]

Trains need to go slow there...even I'll concede THAT.

 

But for some reason I think they put a timer BEFORE trains enter Cypress Hills station--that never used to be there.

There is. Manhattan bound trains always come close to a full stop before Cypress Hills.

[CenSin]

South of 59th St., signals are required to protect the switch coming from 6th Avenue merging onto the express track. The timers ensure an A train doesn't develop excessive speed coming down the hill and risk a collision.

In cases like that, wouldn’t it make sense to activate protection conditionally? Let’s say there are no northbound trains from 7 Avenue to 59 Street–Columbus Circle. If there are no trains using the switch, there shouldn’t be slowdowns. If a train is merging using the switch (or about to), timers should be activated to ensure safe braking distance. This would require the signals to be coordinated from 7 Avenue all the way to 51 Street.

 

The same applies to 36 Street on 4 Avenue.

[Jsunflyguy]

There is. Manhattan bound trains always come close to a full stop before Cypress Hills.

 

Keep in mind signal systems cannot ASSUME that ALL trains will stop at a station.

 

The timer in the station is also protecting the train that is approaching the station at track speed (rules didn't always require trains to slow entering a station if they were bypassing it).

[bstar1]

Timers and Signals are protecting us from possible danger. Remember that Everything is Not Perfect so they're trying best to make sure there's absolutely no accidents at all. Train crashes, derailments, Flying off Elevated Rails including sharp curves , Trains coming into stations too fast may overshoot stop position or something worse, Areas where trains merge with each other. Slow downs and stopping maybe irritable but provides much safety as possible.

[CenSin]

Timers and Signals are protecting us from possible danger. Remember that Everything is Not Perfect so they're trying best to make sure there's absolutely no accidents at all. Train crashes, derailments, Flying off Elevated Rails including sharp curves , Trains coming into stations too fast may overshoot stop position or something worse, Areas where trains merge with each other. Slow downs and stopping maybe irritable but provides much safety as possible.

The most safety possible is provided by trains not moving at all with all the wheels shaved down into squares and chained to the tracks. But obviously, that’s not the point of having a transit system. You must pick a reasonable threshold between light speed and zero velocity, and that is always debatable. The item up for debate is the quantity and location of timers. I feel it’s too much in some places.

[Brooklyn]

There is. Manhattan bound trains always come close to a full stop before Cypress Hills.

 

But why? That one is head scratching, actually.

 

Just slowing down an already slow line.

[SubwayGuy]

In cases like that, wouldn’t it make sense to activate protection conditionally? Let’s say there are no northbound trains from 7 Avenue to 59 Street–Columbus Circle. If there are no trains using the switch, there shouldn’t be slowdowns. If a train is merging using the switch (or about to), timers should be activated to ensure safe braking distance. This would require the signals to be coordinated from 7 Avenue all the way to 51 Street.

 

The same applies to 36 Street on 4 Avenue.

 

Because it doesn't work that way. The timer is not protecting a train diverging from overspeeding. The timer is protecting the rear of a train sitting in 59th St. from an A train coming down the hill at full speed and possibly having a collision. It is also protecting the trailing point switch on the express track (same thing on the local track BTW) from a train coming down the hill at full speed and possibly splitting it, or fouling the switch area. The train's speed has to be regulated at all times such that if the route were cancelled (lineup taken away), a train travelling at maximum POSSIBLE speed (read: not allowed...maximum possible) would still be brought to a stop before any of the above scenarios could take place. Hence timers.

[bstar1]

B and D also joins CPW line.

[Brooklyn]

The most safety possible is provided by trains not moving at all with all the wheels shaved down into squares and chained to the tracks. But obviously, that’s not the point of having a transit system. You must pick a reasonable threshold between light speed and zero velocity, and that is always debatable. The item up for debate is the quantity and location of timers. I feel it’s too much in some places.

Yeah...I'll also add that timers have been put in where none were before--even though there have been no history of accidents.

 

I am EXTREMELY puzzled by the timer they put in at Cypress Hills....this they put in recently. Why? And it's BEFORE Manhattan bound trains enter the station.

 

Some of these timers are headscratching, TBH.

[Eric B]

Probably because people miss the next one, the so-called “hooligan” in the station, which is easy to overlook. With most of those stetions looking pretty much the same, I always just remembered the curve blocked fy the shed. To put a timer outside of the station would be the new warning for the one on the middle of the station.

[SubwayGuy]

Probably because people miss the next one, the so-called “hooligan” in the station, which is easy to overlook. With most of those stetions looking pretty much the same, I always just remembered the curve blocked fy the shed. To put a timer outside of the station would be the new warning for the one on the middle of the station.

 

Yup that timer was always one of the most frequently hit on that line...

[CenSin]

The train's speed has to be regulated at all times such that if the route were cancelled (lineup taken away), a train travelling at maximum POSSIBLE speed (read: not allowed...maximum possible) would still be brought to a stop before any of the above scenarios could take place.

A train already travelling over the switch could not have its line-up taken away. Similarly, simply disallow cancellation of line-up while the train is moving after a certain limit (say 51 Street). If a train is somehow stalled within that area, the line-up can be taken away provided that the train has remained on a track circuit for a certain amount of time (to determine that it’s not moving).

 

I don’t know about splitting switches, but there are plenty of locations where switches are traversed at high speeds (some even on curves). I’m thinking that the limitation of the signalling system is what weighs heaviest; the above plan is certainly one that some high-throughput systems implement, but may not be implementable with what the MTA has to work with.