How do we know terminal capacities?

[realizm]

Four tracks and each pair linked to a dedicated relay area with four storage tracks? 63 TPH could've very well been the level of service in the 50's, when subway usage was at an all time high and both the and (or their predecessor services) terminated at 179th St. I myself do not have schedules from this era, but it seems entirely possible in the age before heavy federal regulation of rail transport, and in a time where trains were regularly doing 110+ MPH service on single track that today is limited to 79MPH operation.

So why does the terminal @ 71st Continental can only handle 20+ on the local alone max on the TPH *with* a connection to Jamaica Yard, another 4 platform station? 179th does not even have that provision with 8 tracks that feed a 4 track platform? That wikipedia reference again is WRONG because first there is no source, second, given that the IND QBL is utilizing old technology from the 1930's it does not render such capabilities, impossible. Third, if you do the math with the timetables, it does not match up by a long shot. Even if the Second System plans called for an extension of the Hillside Ave line, it cannot be possible, no way. The source of this is wrong.

 

I'm ready to change that reference myself I swear, because no sources was made for that claim, impossible, even with the proposed capabilities of the newest state of the art CBTC like the Moscow Metro if I'm correct.

 

How can 8 tracks that feed into a 4 track station allow for 63 TPH with 1930's technology on signaling and such @ 179th? That's the question. Congestion at that station much?

[bobtehpanda]

So why does the terminal @ 71st Continental can only handle 20+ on the local alone max on the TPH *with* a connection to Jamaica Yard, another 4 platform station? 179th does not even have that provision with 8 tracks that feed a 4 track platform? That wikipedia reference again is WRONG because first there is no source, second, given that the IND QBL is utilizing old technology from the 1930's it does not render such capabilities, impossible. Third, if you do the math with the timetables, it does not match up by a long shot. Even if the Second System plans called for an extension of the Hillside Ave line, it cannot be possible, no way. The source of this is wrong.

 

I'm ready to change that reference myself I swear, because no sources was made for that claim, impossible, even with the proposed capabilities of the newest state of the art CBTC like the Moscow Metro if I'm correct.

 

How can 8 tracks that feed into a 4 track station allow for 63 TPH with 1930's technology on signaling and such @ 179th? That's the question. Congestion at that station much?

 

The passenger fumigation that is practiced today was not always practiced (sweeping throughout trains to get rid of passengers). That is currently the major constraint at Forest Hills today - it would otherwise be able to take advantage of the full 30 TPH that the signalling allows, if trains just treated terminals as a normal express stop (and the cutback wouldn't be necessary.) Also, scheduling used to be a lot more intense - at the very least, the old Els ran by "stop on sight" running, which allows much closer running than the rigid fixed-block signalling that the MTA depends on today. Plus, the old trains didn't have governors limiting their speed, and if trains are running faster, they presumably enter stations more often.

 

Rail has actually regressed since the 1930s, because passenger rail, both intra and inter-city, ran much more complex, faster operations. This type of intense operation had its downsides (train accidents were more common in those days) but you win some, you lose some.

[Abba]

@Fan Railer (or anyone else who wants to answer)

 

But the gets backed up at Utica Avenue so often at rush hour, so bad that the constantly beats it there at times. I've been seeing the and those Utica dropouts held on the express tracks between Nostrand and Utica. Sometimes if this occurs, the crew is told to remain in service to New Lots and switches to the local track right after Franklin, which delays the (if its like say 2-3 minutes away).

Yes very big backups there.i live near Kingston ave and many times a or will be sitting on the express tracks for some time.i think there are scheduled New Lots (4)'s.those usually switch to local track after Franklin so as to not have to deal with the relaying at Utica if its not terminating there anyway.however as of late I have seen those New Lots trains going on express tracks.I was on last week that stopped right before Utica for a good minute.think it should have switched after Franklin.There was a 3 right behind it.

[realizm]

bobtehpanda, on 08 Jul 2013 - 9:13 PM, said:

The passenger fumigation that is practiced today was not always practiced (sweeping throughout trains to get rid of passengers). That is currently the major constraint at Forest Hills today - it would otherwise be able to take advantage of the full 30 TPH that the signalling allows, if trains just treated terminals as a normal express stop (and the cutback wouldn't be necessary.) Also, scheduling used to be a lot more intense - at the very least, the old Els ran by "stop on sight" running, which allows much closer running than the rigid fixed-block signalling that the MTA depends on today. Plus, the old trains didn't have governors limiting their speed, and if trains are running faster, they presumably enter stations more often.

 

Rail has actually regressed since the 1930s, because passenger rail, both intra and inter-city, ran much more complex, faster operations. This type of intense operation had its downsides (train accidents were more common in those days) but you win some, you lose some.

Good points.

 

The reality of it is that the IND mad a mistake, a major oversight, in designing and constructing the Queens Boulevard Line as a 4 track line, it really needed to be 6 tracks. Major mishap on the part of the IND, a challenge the MTA is still yet to overcome, as the QBL is the second busiest, most congested line in the United States. (Think of the line that is #1 as the busiest and most congested line in the nation and why the Second Ave Line is being built as others are discussing problems on the and in another aspect of terminal capacity problems .....)

[Guest Lance]

The Queens Boulevard line was designed in the '20s and built mostly in the '30s, finally extended to its present terminal in 1950. During that time, they faced a Depression and a World War which hampered most construction projects not only in the subway, but the city in general. Combine that with the fact that the IND could not possibly foresee the growth that would happen over the decades and you have the situation we currently are dealing with on the line.

[Guest Lance]

Since we're talking about terminal capacity, here's something that should pique your interests: a peak flow map from 1954 showing both actual service and max capacity for the system at the time.

 

http://transitmaps.tumblr.com/post/55177865550/manhattan-flow-1954

[BrooklynIRT]

I like that very much.

 

but how in the world could stub-ended lines like Nostrand be physically capable of handling 30 ten-car trains per hour per direction (looking at the maximum capacity in 1954, not the actual service levels in 1954)!? am I reading the map correctly? were trains able to come into those terminals that quickly back then? WTH?

[Rtrain4thAv]

What about the Bay Ridge-95th Street terminal? How many tph in rush hours? Midday? Off-hours?

[realizm]

The Queens Boulevard line was designed in the '20s and built mostly in the '30s, finally extended to its present terminal in 1950. During that time, they faced a Depression and a World War which hampered most construction projects not only in the subway, but the city in general. Combine that with the fact that the IND could not possibly foresee the growth that would happen over the decades and you have the situation we currently are dealing with on the line.

 

According to US census statistics that are cited  (click on link, it's a long reference) for that period it states that the queens population doubled from the population of Queens more than doubled in the 1920s, from 470,000 in 1920 to well over 1 million in change in 1930. The line apparrently was opened in 1933. Given the fact that the population in Queens has experienced a practical 50% growth in a decade leaves me to wonder how did the IND and the City of New York make the mistake in not forseeing the obvious and why they should have did something with the final construction of the QBL to accommodate for anticipated growth of Queens into the second most densely populated borough next to Brooklyn today. That is something that continues to baffle me.

 

What about the Bay Ridge-95th Street terminal? How many tph in rush hours? Midday? Off-hours?

 

It's all from the MTA timetables. If you caculate the number of departures from 95th Street from this official source you can see what is the numbers in TPH given a certain hour of the week or weekend.

 

Link: http://www.mta.info/nyct/service/pdf/trcur.pdf

[CastleHillAvenue]

we have to really consider the effects of the terminal on the human psyche. the new R410 is truly going to enhance the structure of modern day travel. Churchill can be felt for miles down the mississippi and Far rockaway is devine.

[CastleHillAvenue]

we have to really consider the effects of the terminal on the human psyche. the new R410 is truly going to enhance the structure of modern day travel. Churchill can be felt for miles down the mississippi and Far rockaway is devine.

Sorry, please disregard this. Thank you.

[AndrewJC]

Four tracks and each pair linked to a dedicated relay area with four storage tracks? 63 TPH could've very well been the level of service in the 50's, when subway usage was at an all time high and both the and (or their predecessor services) terminated at 179th St. I myself do not have schedules from this era, but it seems entirely possible in the age before heavy federal regulation of rail transport, and in a time where trains were regularly doing 110+ MPH service on single track that today is limited to 79MPH operation.

 

I guarantee that the QBL express has never carried 63 trains per hour!

 

The passenger fumigation that is practiced today was not always practiced (sweeping throughout trains to get rid of passengers). That is currently the major constraint at Forest Hills today - it would otherwise be able to take advantage of the full 30 TPH that the signalling allows, if trains just treated terminals as a normal express stop (and the cutback wouldn't be necessary.) Also, scheduling used to be a lot more intense - at the very least, the old Els ran by "stop on sight" running, which allows much closer running than the rigid fixed-block signalling that the MTA depends on today. Plus, the old trains didn't have governors limiting their speed, and if trains are running faster, they presumably enter stations more often.

The signal system currently in place on the QBL is, with some relatively small modifications, the same signal system that was in place when the line opened. (OK, so it's not entirely fair to treat the introduction of three new interlockings as "relatively small" - but aside from them, it's pretty much original.)

 

Since we're talking about terminal capacity, here's something that should pique your interests: a peak flow map from 1954 showing both actual service and max capacity for the system at the time.

 

http://transitmaps.tumblr.com/post/55177865550/manhattan-flow-1954

 

I enjoy that map a lot, but I've seen no evidence that trains actually ran at those frequencies. The brand new NYCTA may have simply been trying to impress by scheduling more service than could possibly have operated.

 

As for the capacity notations, are they theoretical or practical? The theoretical capacity is only achievable if trains follow each other as closely as the signal system allows, without even brief interruptions. In practice, the capacity is a bit lower. My signal engineer acquaintances have told me that they aim for a theoretical 40 tph in most of the design work they do for the subway, but the practical capacity is only 30 tph.

 

It's all from the MTA timetables. If you caculate the number of departures from 95th Street from this official source you can see what is the numbers in TPH given a certain hour of the week or weekend.

 

Link: http://www.mta.info/nyct/service/pdf/trcur.pdf

 

The timetables give the scheduled frequency, not the capacity (although these days you can be pretty confident that the former is no greater than the larger). The R runs at 10 tph during rush hours, 6 tph off-peak, but the capacity of the terminal is probably higher than that.

[Jsunflyguy]

Surely fumigation could be gotten rid of for trains continuing on revenue track?