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| Re: Speeding up timers (1495269) | |
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Re: Speeding up timers |
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Posted by Andrew Saucci on Wed Dec 12 19:25:51 2018, in response to Re: Speeding up timers, posted by randyo on Wed Dec 12 16:12:25 2018. Many people are under the misapprehension that two parties can agree to anything and it is enforceable. A really good lawyer can go through a contract and identify unenforceable clauses. That doesn't necessarily mean that one can get them removed, but knowing that they are unenforceable can be useful.The classic example, of course is a slavery contract. It doesn't matter if such a thing is printed on legal-sized paper, witnessed by a notary and three doctors who agree that the parties are of sound mind and free to enter into an agreement, and so on-- it simply is unenforceable. |
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| (1495645) | |
Re: Speeding up timers |
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Posted by WayneJay on Wed Dec 12 22:22:08 2018, in response to Re: Speeding up timers, posted by Steve B-8AVEXP on Mon Dec 10 19:48:25 2018. Agreed! It's been gone for far too long. I'm often thinking of those good 'ol days when NYCTA trains actually moved along at decent speeds, and all of those great express runs. |
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Posted by Bill from Maspeth on Wed Dec 12 22:39:26 2018, in response to Re: Speeding up timers, posted by Steve B-8AVEXP on Mon Dec 10 19:48:25 2018. Let's not get carried away. The trains themselves are not getting any faster, but many speed restrictions are being eased. Field shunting is not being restored. |
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iPhone 6 (4.7 Inch) Premium PU Leather Wallet Case - Red w/ Floral Interior - by Notch-It |
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| (1495648) | |
Re: Speeding up timers |
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Posted by Express Rider on Wed Dec 12 23:04:32 2018, in response to Re: Speeding up timers, posted by WayneJay on Wed Dec 12 22:22:08 2018. iawtp!we all rememeber those days, and hope performance returns to what it was.....moving people in the quickest way possible around the city and making uber become nothing but a memory.... |
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| (1495653) | |
Re: Speeding up timers |
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Posted by Express Rider on Thu Dec 13 00:42:24 2018, in response to Re: Speeding up timers, posted by Bill from Maspeth on Wed Dec 12 22:39:26 2018. do you think field shunting ever will be restored, as part of "improvements" or what is in reality, restoration of technology for appropriate faster service? |
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| (1495669) | |
Re: Speeding up timers |
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Posted by South Brooklyn Railway on Thu Dec 13 06:04:36 2018, in response to Re: Speeding up timers, posted by MorningsideHeightsM100 on Wed Dec 12 09:28:13 2018. I'm sure if they were to rebuild the roadbed, it wouldn't be as bad. |
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| (1495694) | |
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Posted by MorningsideHeightsM100 on Thu Dec 13 10:25:30 2018, in response to Re: Speeding up timers, posted by South Brooklyn Railway on Thu Dec 13 06:04:36 2018. They already have issues delivering service because its only two tracks the whole length, and people aren't happy when the trains are late and don't meet the ferry. |
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| (1495696) | |
Re: Speeding up timers |
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Posted by Steamdriven on Thu Dec 13 10:53:29 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Mon Dec 10 22:23:09 2018. Welll, the R44 test train made it to 87 3/4 mph. Another 1/4 mph and it would have escaped the '70s, bringing it back to Now which was the Future.* yeah I know it was on LIRR track, etc. |
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Re: Speeding up timers |
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Posted by Bill from Maspeth on Thu Dec 13 15:24:13 2018, in response to Re: Speeding up timers, posted by Express Rider on Thu Dec 13 00:42:24 2018. Field shunting, IMO, will still be disabled because NYCT is fooling the public into believing that the trains will be SO much faster now. They are not going to remind the public field shunting is here to stay.Don't get me wrong, if I still were a train operator I would be satisfied over the improvement but I certainly wouldn't be overjoyed. The improvement will take a minute or 2 off trips, but allowing the trains to run without field shunting would at least double the improvement. |
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| (1495748) | |
Re: Speeding up timers |
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Posted by Bill from Maspeth on Thu Dec 13 15:29:19 2018, in response to Re: Speeding up timers, posted by Express Rider on Wed Dec 12 23:04:32 2018. Performance will not return to what it was because nothing was said about putting back field shunting. |
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| (1495750) | |
Re: Speeding up timers |
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Posted by MorningsideHeightsM100 on Thu Dec 13 15:40:52 2018, in response to Re: Speeding up timers, posted by Bill from Maspeth on Thu Dec 13 15:29:19 2018. What IS field shunting? |
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| (1495755) | |
Re: Speeding up timers |
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Posted by AlM on Thu Dec 13 15:51:53 2018, in response to Re: Speeding up timers, posted by Bill from Maspeth on Thu Dec 13 15:24:13 2018. Remember that the speed-ups from low speeds to moderate speeds are more value than comparable speed-ups from moderate to high speed.If a one-mile run can be speeded up from 20 mph to 30 mph, that saves a minute. But speeding it up from 30 to 40 only saves another 30 seconds. |
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| (1495762) | |
Re: Speeding up timers |
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Posted by trains61 on Thu Dec 13 16:51:35 2018, in response to Re: Speeding up timers, posted by MorningsideHeightsM100 on Thu Dec 13 15:40:52 2018. Field Weakening:The DC motor can be made to run faster than the basic "balancing speed" achieved whilst in the full parallel configuration without any resistance in circuit. This is done by "field shunting". An additional circuit is provided in the motor field to weaken the current flowing through the field. The weakening is achieved by placing a resistance in parallel with the field. This has the effect of forcing the armature to speed up to restore the balance between its magnetic filed and that being produced in the field coils. It makes the train go faster. Various stages of field weakening can be employed, according to the design of the motor and the intended purpose. Some locomotives used as many as six steps of field weakening. The Lurker`s Guild Technical Division |
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| (1495789) | |
Re: Speeding up timers |
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Posted by Steve B-8AVEXP on Thu Dec 13 20:23:19 2018, in response to Re: Speeding up timers, posted by BILLBKLYN on Wed Dec 12 00:32:41 2018. Me three, although it wouldn't be the same without the R-10s. |
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| (1495790) | |
Re: Speeding up timers |
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Posted by Steve B-8AVEXP on Thu Dec 13 20:25:36 2018, in response to Re: Speeding up timers, posted by Bill from Maspeth on Wed Dec 12 22:39:26 2018. I'm just hoping it won't be a case of, "you'll get there - eventually," anymore. |
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Re: Speeding up timers |
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Posted by SUBWAYMAN on Fri Dec 14 18:17:07 2018, in response to Re: Speeding up timers, posted by Bill from Maspeth on Thu Dec 13 15:24:13 2018. Doesn't field shunting use more energy? |
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Re: Speeding up timers |
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Posted by MTA T on Fri Dec 14 22:32:50 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Tue Dec 11 04:49:50 2018. I believe some timers exist to reduce wear on switches rip. |
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Re: Speeding up timers |
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Posted by VictorM on Fri Dec 14 23:42:41 2018, in response to Re: Speeding up timers, posted by SUBWAYMAN on Fri Dec 14 18:17:07 2018. Yes, it does. I read somewhere that NYC Transit claimed disabling field shunting reduced energy consumption by 12½%. |
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| (1495943) | |
Re: Speeding up timers |
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Posted by Henry R32 #3730 on Sat Dec 15 00:15:13 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Tue Dec 11 04:49:50 2018. *Unpopular opinion*: Would closing whole subway lines at night for proper maintenance be better if it meant higher speeds during the daytime?Kindof like FastTrack on steroids. It would actually work out if it were only express tracks worked on to maintain higher level of speeds, since those are less necessary at night anyway. |
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| (1495962) | |
Re: Speeding up timers |
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Posted by Dyre Dan on Sat Dec 15 08:14:41 2018, in response to Re: Speeding up timers, posted by Henry R32 #3730 on Sat Dec 15 00:15:13 2018. They would need to erect barriers between the express and local tracks, otherwise the local trains would have to slow down considerably when they passed workers on the express tracks. Most express tracks already close at night, would nightly cleaning/maintenance really improve or speed up service on them?As for timers, the ones they most need to get rid of or speed up are on the 4/5 tracks leaving 125th St. in both directions. |
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| (1495966) | |
Re: Speeding up timers |
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Posted by AlM on Sat Dec 15 09:38:55 2018, in response to Re: Speeding up timers, posted by Henry R32 #3730 on Sat Dec 15 00:15:13 2018. Would closing whole subway lines at night for proper maintenanceWhat percent of the 8,760 hours in a year are really required for maintenance? Aren't selected weekends plus occasional Fast Tracks sufficient? |
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| (1495970) | |
Re: Speeding up timers |
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Posted by Stephen Bauman on Sat Dec 15 11:09:22 2018, in response to Re: Speeding up timers, posted by Dyre Dan on Sat Dec 15 08:14:41 2018. the ones they most need to get rid of or speed up are on the 4/5 tracks leaving 125th St. in both directions.I cannot speak for the uptown direction. The timers on the downtown side are needed because the 4/5 out of 125th must diverge south of the station to reach the Lex express tracks. The speed for a diverging switch is usually 10 mph. Unfortunately, the switch is located somewhat south of the station. The train operator will usually limit the speed to 10 mph from the station until the switch is cleared. This effectively limits the Lex express to around 33 tph, instead of the nominal 40 tph. The interlocking is located sufficiently close to the station so that the station entrance isn't cleared until the 4/5 clears it. The station entrance has timers to somewhat mitigate this problem. If the train has cleared the station but not the interlocking, there is a timer for restricted speed. The timer isn't in operation, if there are no trains between the station and the south end of the interlocking. |
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| (1495974) | |
Re: Speeding up timers |
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Posted by r33/r36 mainline on Sat Dec 15 12:11:42 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Sat Dec 15 11:09:22 2018. Uptown the 4/5 line gotta switch tracks as well. |
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| (1496067) | |
Re: Speeding up timers |
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Posted by Dyre Dan on Sun Dec 16 07:41:18 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Sat Dec 15 11:09:22 2018. It may be technically a diverging switch, but it is practically straight track in terms of geometry. I commuted to school over that switch in the 1960s, and to work in the 1970s and '80s, and that speed restriction wasn't in place. I think it started in the '90s, although I'm not sure. But if it could be negotiated safely at higher speeds in the past, why not now? |
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| (1496089) | |
Re: Speeding up timers |
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Posted by Stephen Bauman on Sun Dec 16 11:27:25 2018, in response to Re: Speeding up timers, posted by Dyre Dan on Sun Dec 16 07:41:18 2018. I made several field trips in the 1998-2002 period. The object was to determine what was limiting am rush hour Lex express service levels. Operator variability, scheduled and operating merging conflicts made it difficult to track the actual trains to their schedules. I also did off peak studies at the various stations. I'm grateful that the static and run time feeds no longer make it necessary to get to remote platforms at 7am. Moreover, it's possible to track individual trains for their entire runs.The off peak studies showed that operator variability was the primary problem to efficient operation. The off peak studies confirmed that the existing signal system was by and large capable of 40 tph/30 sec dwell time operation with a few exceptions at a couple of stations. 125th turned out to be a surprise. 14th St was everyone's candidate. It turns out 14th St isn't much of an impediment. Some skeptics went out and confirmed my measurements. There isn't much bang for the buck (service level wise) in straightening out the curves to eliminate the gap fillers. |
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| (1496092) | |
Re: Speeding up timers |
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Posted by pelham Exp on Sun Dec 16 12:16:58 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Sun Dec 16 11:27:25 2018. Operator variability: When I did my internship back in the day at Command there was always one conductor day in and day out on the Pelham Line who radioed in saying they were delayed because of heavy passenger loads..he was notorious for starting a Conga line down Lexington Av. Those of you who worked with him (some who post here have) can attest it wasn't the operator it was the conductor in this case. |
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| (1496094) | |
Re: Speeding up timers |
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Posted by SUBWAYMAN on Sun Dec 16 12:26:15 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Sun Dec 16 11:27:25 2018. Wouldn't lengthening the downtown platform at 14th St/Union Sq be expensive? |
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| (1496171) | |
Re: Speeding up timers |
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Posted by BusRider on Sun Dec 16 19:16:24 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Sun Dec 16 11:27:25 2018. How did you study the operator variability? |
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Posted by Stephen Bauman on Sun Dec 16 21:34:09 2018, in response to Re: Speeding up timers, posted by BusRider on Sun Dec 16 19:16:24 2018. How did you study the operator variability?I measured stopping and acceleration times with a stop watch at the same stations during off peak hour when there was no traffic ahead. The stopping time was interval from when a train entered the station until it came to a complete stop. The acceleration time was the interval from when the train started to move until it ran sufficiently ahead to permit another train to enter the station. This was the instant when either the tripper at the station exit came up or when the signal within the station with only the red and yellow aspects turned yellow. Generally the standard deviation was around 33% of the mean value for each measurement. |
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Re: Speeding up timers |
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Posted by BusRider on Sun Dec 16 23:37:55 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Sun Dec 16 21:34:09 2018. Interesting, thank you. How long were the merges? |
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Posted by Stephen Bauman on Mon Dec 17 08:14:11 2018, in response to Re: Speeding up timers, posted by BusRider on Sun Dec 16 23:37:55 2018. How long were the merges?Long as in distance, time to clear? It takes about 1 minute for a 600' train to clear a 350 foot long interlocking at 10 mph. That's (350 + 600)/(10 x 1.47) = 64.6 sec. A shorter 510 foot train would take 54 seconds. The merging time determines how accurately trains must be on schedule to prevent merging conflicts (assuming they are not built into the schedule). Let's say 120 second headways (30 tph) means that there's 1 minute free time between the leader clearing the interlocking and the follower's arrival. If both the leader and follower were within 30 seconds of the schedule, there would never be any merging delays. There would be 30 seconds of free time for 90 second headways (40 tph). Trains would need to be within 15 seconds of schedule to eliminate merging delays. |
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Posted by BusRider on Mon Dec 17 08:33:11 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Mon Dec 17 08:14:11 2018. Yes, that's what I meant my apologies. Now when you take the 33% crew variability, how can you ensure that 15 seconds? |
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Posted by MainR3664 on Mon Dec 17 09:32:48 2018, in response to Re: Speeding up timers, posted by AlM on Thu Dec 13 15:51:53 2018. Hey, I regularly ride the R (W if it shows up first..) from Whitehall to 8th. That run seriously crawls. If it could get better to even a small, but noticeable degree, I'd be happy. |
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Re: Speeding up timers |
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Posted by Stephen Bauman on Mon Dec 17 11:38:39 2018, in response to Re: Speeding up timers, posted by BusRider on Mon Dec 17 08:33:11 2018. Now when you take the 33% crew variability, how can you ensure that 15 seconds?You train the crews and provide them with the equipment to reduce that variability. Schedules have 3 major problems. 1. they have built in merging conflicts. 2. they don't accurately reflect train speed by padding station to station running times 3. they use 30 second resolution for times when they should be down to the second Once the schedule problems are resolved, then and only then will it be possible to train the crews to operate according to a viable schedule. |
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Re: Speeding up timers |
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Posted by BusRider on Mon Dec 17 12:41:02 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Mon Dec 17 11:38:39 2018. Isn't built-in merge conflicts a good thing?Without the use of static/feeds scheduling down to the second would need at least 1,000 man observations to have something accurate when schedule building. I've done a similar study to yours at Borough Hall and trains seemed sl erratic I ended it early. |
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Posted by Stephen Bauman on Mon Dec 17 15:26:47 2018, in response to Re: Speeding up timers, posted by BusRider on Mon Dec 17 12:41:02 2018. Isn't built-in merge conflicts a good thing?Merging conflicts mean delays. Delays mean longer running time. It costs NYCT approximately $2500/hr to operate a 10 car train, according to the NTD 2017 profile study. An unnecessary 1 minute delay, due to a merging conflict costs $41.67. Without the use of static/feeds scheduling down to the second would need at least 1,000 man observations to have something accurate when schedule building. There are lots of ways to do this. You can put an event recorder at each station to timestamp train arrivals and departures. You just got to make sure the clock for each event recorder is correct down to a fraction of a second. That's essentially the old tech way of today's GTFS-RT feed. You can also calculate the running time from the permitted speeds between each station and the acceleration/braking rates. The biggest hurdle is realizing there's a need for such information. The second biggest hurdle is using the data after it's obtained. I've done a similar study to yours at Borough Hall and trains seemed sl erratic I ended it early. There was a saying, when I started my engineering career, "if you can't be good then be consistent." If things are consistent then things can be made better. There's very little chance of discovering what's wrong, if there's no consistency. I found there was very little consistency on even the most basic operations, e.g. braking/acceleration at stations with no traffic. There's also very little chance for order, when trains departures from the terminal are unpredictable. |
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Re: Speeding up timers |
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Posted by Steamdriven on Mon Dec 17 16:25:19 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Mon Dec 17 08:14:11 2018. Serious, not snark question:Why can 'smoothed' switches* be installed, and trains proceed over them at 17 or (better) 20 mph? Time spent at 10 mph drags down average speed. When you consider that a train will have 500-1000 people on it even at the edges of rush hour and each is wasting time worth $25 to well over $100/hr (different figure if counting wages vs productivity), a train may use from 10 to over 100 thousand $ worth of rider's time per hour. Using a speculative 50K/hr total value for passenger's time, that's about - - - $800/minute, or $14/second. There's also the cost of braking 900,000 pounds of train from, say, 25 to 10 mph, then accelerating it again. Multiply by over 100 trains per day. Including excessively slow timer restrictions (even after 'fixing') plus crawling over switches, there are numerous minutes wasted on an average run. Personally, I think passenger's time is worth more than the above, because people in NY are over-scheduled and stressed out. They need a few more minutes of sleep, not time standing on a barely moving train. * By smoothed I mean "whatever changes need to be made to allow for normal operation at the target speed, without the typical standing passenger falling over". |
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Re: Speeding up timers |
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Posted by orange blossom special on Mon Dec 17 20:35:17 2018, in response to Re: Speeding up timers, posted by randyo on Tue Dec 11 00:19:24 2018. Not to mention the fender benders in the parking lots when they park the trains! |
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Re: Speeding up timers |
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Posted by Andrew Saucci on Mon Dec 17 21:20:19 2018, in response to Re: Speeding up timers, posted by Stephen Bauman on Mon Dec 17 15:26:47 2018. One thing that automated trains can give is consistency. Presumably, every automated train will brake and accelerate exactly the same way every time in the absence of compelling reasons to deviate from the standard. They don't add a random number generator into the programming to simulate the differing styles of various human train operators (sort of what I did when I created my harness race simulation program may years ago). In fact, even the same person could operate a train differently at different times depending on his mood or mental or physical condition. |
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Re: Speeding up timers |
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Posted by Stephen Bauman on Mon Dec 17 23:38:41 2018, in response to Re: Speeding up timers, posted by Andrew Saucci on Mon Dec 17 21:20:19 2018. Presumably, every automated train will brake and accelerate exactly the same way every time...There are ways humans can operate trains within 15 seconds of a schedule that is free of merging conflicts. Some methods use feedback that enables an operator to compare his time to what's expected. It's it's inexpensive to build and operate, so the MTA would not be interested. Tokyo just trains its operators to be accurate to within a second. That saves the cost of equipping the system with inexpensive feedback devices. |
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