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| (1639913) | |
Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Wed Mar 12 16:48:27 2025 Have they identified the source of the R160's wheel wear and what have they done about it? |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by zac on Wed Mar 12 19:05:39 2025, in response to Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 16:48:27 2025. It's been a bit of a mystery as to what happened. There is some sense that it is ATO operation and hard braking that has caused it, but if that were the case both passengers and crew would have noticed. These cars have been in service 15-20 years already and only now are having this problem so it must be something that changed recently, and there are a finite number of changes, a small one at that.In my work we'd when something suddenly stopped working that would be the first place we'd look, "What changed???" That would be too logical for the MTA though. |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Wed Mar 12 19:46:09 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Wed Mar 12 19:05:39 2025. . It's been a bit of a mystery as to what happened. There is some sense that it is ATO operation and hard braking that has caused it, but if that were the case both passengers and crew would have noticed. These cars have been in service 15-20 years already and only now are having this problem so it must be something that changed recently, and there are a finite number of changes, a small one at that.In my work we'd when something suddenly stopped working that would be the first place we'd look, "What changed???" That would be too logical for the MTA though. Were specific series of 160's assigned to let's say the F and another set to the E or could they be reflagged as they were put in service each day? If there was no clear assignment, that would make contact tracing harder. Back in January, it was suggested that there was a specific section of track that was causing wheel wear. If that's the case, I would have simply not used that section and operated the affected lines in two sections and institute bustuition to provide a smooth trip. |
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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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R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Wed Mar 12 20:25:39 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 19:46:09 2025. About a week ago, this Brooklyn Daily Eagle article suggests the shortening of R trains as a result of R160's in rehab. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by randyo on Thu Mar 13 02:02:55 2025, in response to R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 20:25:39 2025. I can’t see how they could run 8 car trains on the R since they are in 5 car units and certain dedicated consists are required for the CBTC to work properly. Even if it were possible, what advantage would there be to it since the excess cars removed would probably not be able to be used on the trains currently in E and F service anyhow. Back when the pre NTTs were running it would have been possible to simply cut 2 car married pairs from 10 car trains and assemble them into either 8 or 10 car trains as needed, but that is not as simple with the NTTs. |
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| (1639928) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by New Flyer #857 on Thu Mar 13 07:00:53 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by randyo on Thu Mar 13 02:02:55 2025. It sounds like the R would borrow from ENY (perhaps interchanging with the M at Forest Hills). Are there enough 4-car sets to spare from ENY now that the R179s and R211s are around? Even if they only have a couple of sets to spare it might happen if Jamaica yard is really struggling. |
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| (1639938) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by zac on Thu Mar 13 09:19:11 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by New Flyer #857 on Thu Mar 13 07:00:53 2025. It was to be the 8 car R179s from the C as there are 10 car R211s and still the R46s to replace them.It sounds like the issue is abating as some runs that were cut are running again. I still think the root cause is that someone or group f'ed up big time. Remember the issue with the R211s and the leaks that caused the wheels to flat? I still contend that they f'ed up the testing by testing a train that didn't have the production wheels on it. Who messed up that testing? That would have broken protocol and been flagged during an audit at my job. If we tested something and it passed, then any changes made before it went into production would need to be tested too as thoroughly as the original test. My guess is something like this happened again, and maybe even the same group which is why it is so hush hush. Did they test ATO with a differently configured train? Did they not add passenger weight? OMG, I think I just figured it out. I am willing to bet that the cause of this will be the testing did not include the passenger weight. |
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| (1639942) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 11:10:59 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Thu Mar 13 09:19:11 2025. . Did they not add passenger weight? OMG, I think I just figured it out. I am willing to bet that the cause of this will be the testing did not include the passenger weight.Interesting. The weight of a 160 is about 85,000 lbs. The capacity of the 160 is around 200 passengers. Assuming an average weight of 150, that would add 30,000 lbs when the car has a near full load. That's an extra 35% weight. But when they test cars, they would be hard pressed to get 200 times (the # of cars being tested) passengers to go for a test ride. So I would guess there's some kind of conversion factor for an empty train test results to a fully loaded test results. Plus if you are referring to the 160's, the testing was a long time ago. |
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| (1639947) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Steamdriven on Thu Mar 13 13:10:39 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 11:10:59 2025. They can load sandbags or such to simulate passengers. That's a standard practice. Maybe someone didn't wanna bother. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 13:41:54 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Steamdriven on Thu Mar 13 13:10:39 2025. They can load sandbags or such to simulate passengers. That's a standard practice. Maybe someone didn't wanna bother.I know when they do a 5 year elevator safety test, they bring in heavy weights to simulate passenger capacity. But do they actually simulate a capacity load when testing new subway cars? |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Thu Mar 13 14:52:38 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 11:10:59 2025. The capacity of the 160 is around 200 passengers.Perhaps, if all 200 were lying flat and stacked one on top of one another up to the ceiling. The service level capacity for 60 footers is 145, as per NYCTA. That's still a very tight fit. |
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| (1639954) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by zac on Thu Mar 13 16:16:15 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 11:10:59 2025. I'm not saying for the initial test of the 160s, but for the ATO testing done with them. That's why it is a new problem. They turned on ATO based on tests of empty trains, but the trains themselves couldn't take the stress it created when full. And QBL is always full. And they probably didn't do a passenger load test because it was done when the 160s were new. |
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| (1639955) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by zac on Thu Mar 13 16:18:06 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Thu Mar 13 14:52:38 2025. Let's play with those numbers though. Paul said 200 passengers at 150 pounds, I'd say 150 passengers at 200 pounds! You get the same weight that way. It may be less on a full train so instead of 35% increase it is 25%. That's still significant. |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Railman718 on Thu Mar 13 17:10:26 2025, in response to Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 16:48:27 2025. Dont Mind me im just eating my popcorn reading the Comments.... |
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| (1639957) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Railman718 on Thu Mar 13 17:10:50 2025, in response to R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 20:25:39 2025. Man this Popcorn is good.... |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 17:48:49 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Railman718 on Thu Mar 13 17:10:26 2025. Our goal is always to exceed your expectations |
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| (1639960) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 18:03:57 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Thu Mar 13 14:52:38 2025. The capacity of the 160 is around 200 passengers.Perhaps, if all 200 were lying flat and stacked one on top of one another up to the ceiling. The service level capacity for 60 footers is 145, as per NYCTA. That's still a very tight fit. I was going by Wickyleaks who reported 48 seated 198 standing vertically, not including surfers on the car roof and peeers and smokers outside of the storm door. |
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| (1639961) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 18:13:52 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Thu Mar 13 16:18:06 2025. The capacity of the 160 is around 200 passengers.Perhaps, if all 200 were lying flat and stacked one on top of one another up to the ceiling. The service level capacity for 60 footers is 145, as per NYCTA. That's still a very tight fit. |
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| (1639962) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 18:19:14 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Thu Mar 13 16:16:15 2025. 'm not saying for the initial test of the 160s, but for the ATO testing done with them. That's why it is a new problem. They turned on ATO based on tests of empty trains, but the trains themselves couldn't take the stress it created when full. And QBL is always full. And they probably didn't do a passenger load test because it was done when the 160s were new.When did QBL go to CBTC full time? Also, are you saying that under CBTC the cars would be under more stress than operator control? Is the braking harsher? |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Railman718 on Thu Mar 13 18:55:03 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 17:48:49 2025. Mine are extremely high... |
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| (1639971) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by zac on Thu Mar 13 21:32:06 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 18:19:14 2025. It's been CBTC for a while now, but ATO is more recent. A TO could sense the braking and because of rules and fear of overrunning the platform would apply sooner. ATO just does what it is told and was probably told to apply brakes harder based on testing with empty trains. That's my latest theory. I've also said somewhere that you'd think that both passengers and crew would have noticed the hard braking.In any case this is all speculation on my part, but I also got paid the big bucks because my speculation was always right on my real job even in areas where I had no prior knowledge. Gather a few facts, apply some prior similar experiences, add intuition, and come up with an answer. |
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| (1639972) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 22:04:54 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Thu Mar 13 21:32:06 2025. I'm just speculating now when I say that I thought that ATO or whatever you want to call it would take into consideration how loaded the train is and adjust its braking accordingly. It seems that a heavily loaded train would require more dynamic or frictional braking than a lightly or moderately loaded train. |
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| (1639973) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Thu Mar 13 22:35:55 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Thu Mar 13 21:32:06 2025. ATO just does what it is told and was probably told to apply brakes harder based on testing with empty trains.The BRT standards had a car load detector so that same brake handle position applies brake force that is proportional to the load in the car. All subsequent equipment for the BMT, IND and IRT have had a similar mechanism. This means the brake handle in the same position will provide the same deceleration regardless of the car load. The NTT train signals are based on brake handle position. Ditto for throttle position. So, the brakes should not see any difference regardless whether operated by a T/O or CBTC. |
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| (1639974) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Thu Mar 13 22:50:36 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Thu Mar 13 22:35:55 2025. The BRT standards had a car load detector so that same brake handle position applies brake force that is proportional to the load in the car. All subsequent equipment for the BMT, IND and IRT have had a similar mechanism. This means the brake handle in the same position will provide the same deceleration regardless of the car load.Are you saying that the brake handle positions were definable or notched rather than continuous? I know the R1/9 controller had 3 notches, but I didn't know that the brake valve had discrete positions. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by LuchAAA on Thu Mar 13 23:06:11 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Thu Mar 13 22:35:55 2025. I think the load mechanism is called the "slack adjustor". |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Train Dude on Fri Mar 14 00:48:43 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Railman718 on Thu Mar 13 17:10:26 2025. I can't believe that with all the collective rapid transit knowledge that exists on Subchat, that the cause has not been revealed yet. It's so obvious. |
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| (1639983) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by randyo on Fri Mar 14 01:53:59 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 22:04:54 2025. Well the load sensors on the cars are supposed to adjust the braking force based on the passenger loading of the car so there shouldn't be any problems. |
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| (1639984) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by randyo on Fri Mar 14 02:00:44 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 22:50:36 2025. Non self lapping brake valves like the M-19 (Qs) and the ME-23 (ABs, Ds, Lo-Vs and R-1/9s) have specific positions that require “fanning” of the brake valve between service and lap positions (lap bing a pneumatic holding position). SMEE equipment (and the Multis before them) had a self lapping feature in which braking effort is based on the position of the brake valve. |
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| (1639985) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by randyo on Fri Mar 14 02:02:03 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by LuchAAA on Thu Mar 13 23:06:11 2025. The slack adjuster is an entirely different device that adjusts brake cylinder travel to compensate for brake shoe wear. |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Railman718 on Fri Mar 14 05:03:33 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Fri Mar 14 00:48:43 2025. I’m surprised myself with so many TSSs, RCIs, Dispts ,Supts who post here sharing their collective knowledge on the NYC Subway system… |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Fri Mar 14 06:01:04 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Railman718 on Fri Mar 14 05:03:33 2025. |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Steve B-8AVEXP on Fri Mar 14 06:01:49 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Fri Mar 14 06:01:04 2025. I was wondering when you'd resort to scrolling text again.:) |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Fri Mar 14 06:13:31 2025, in response to Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Steve B-8AVEXP on Fri Mar 14 06:01:49 2025. This was a special occasion. I would have liked to throw in some alternate & up and down motion also. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Fri Mar 14 08:01:38 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 22:50:36 2025. Sorry, I've lost the NTT LonWorks signal specs that I downloaded 30+ years ago from a dial up bulletin board. I cannot answer whether there were 2, 4, or 128 different brake handle positions transmitted in the LonWorks signal.I do remember the general design philosophy and its shortcomings. That's enough to answer whether the brakes know the difference as to whether the signal it received originated from an operator or CBTC. |
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| (1639999) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Fri Mar 14 08:02:08 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Thu Mar 13 22:50:36 2025. Sorry, I've lost the NTT LonWorks signal specs that I downloaded 30+ years ago from a dial up bulletin board. I cannot answer whether there were 2, 4, or 128 different brake handle positions transmitted in the LonWorks signal.I do remember the general design philosophy and its shortcomings. That's enough to answer whether the brakes know the difference as to whether the signal it received originated from an operator or CBTC. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Train Dude on Fri Mar 14 09:17:31 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Thu Mar 13 21:32:06 2025. Understanding that my knowledge might be more than a decade old, let me correct one of your comments. When testing braking on railcars, procedures call for testing in AW0 and AW3 load conditions which calls for loading weights onto cars to simulate heavy load conditions. |
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Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Steamdriven on Fri Mar 14 12:48:17 2025, in response to Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 16:48:27 2025. The cheapest penalty box on 4 tires you can buy in the USA has a fancy anti skid-slide system that works at all vehicle weights and road conditions. ABS was invented before anyone here (and even in Congress) as born, then it went into mass production in the 1940s on the B-47.ABZ was mass produced in the '40s, why isn't it on all subway cars now? |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by zac on Fri Mar 14 18:33:58 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Fri Mar 14 09:17:31 2025. But were they testing the braking? Or just the ATO program? The braking on the cars was tested 15+ years ago. This could be the point of failure. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by LuchAAA on Fri Mar 14 20:11:30 2025, in response to R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by heypaul on Wed Mar 12 20:25:39 2025. It would be interesting to see 8 car R's.When 8 car M trains stop at certain local stops, especially on Queens Corridor, passengers wait at the far end of the platform where only 10 car trains stop. A courteous T/O will give a few short horn blasts to cue them to run towards the train. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Fri Mar 14 20:36:56 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Fri Mar 14 09:17:31 2025. When testing braking on railcars, procedures call for testing in AW0 and AW3 load conditions which calls for loading weights onto cars to simulate heavy load conditions.I wonder whether a test at two loading weights is sufficient from a purely engineering perspective. The railcar contains an energy storage component - the suspension springs. This means there are resonance frequencies that may be loading weight dependent. There are damping components that make resonance oscillations imperceptible to the passenger. However, these damped oscillations may have a subtle effect on the wheel-rail interface and on braking. I can think of an analogous situation back when I participated in organized endurance bicycling events. I was traveling fast on a blue stone road. The road wasn't smooth like asphalt but it wasn't bumpy like cobblestones. I applied my brakes and did not experience an instant speed reduction. The reason nothing happened was because both wheels were slightly off the pavement due to the roadway surface and my high pressure tires. Without the road contact, the pressure exerted by the brake pads was sufficient to lock the wheels. Had I held on to the brakes both wheels would have skidded, when the bike returned to the ground. The solution was to let go of the brakes, so that they could roll in the 1/4 second it took the wheels to regain contact with the road. I can conceive of something similar with a railcar. The wheels don't have lift off the rails. The car body's weight might be reduced on the truck, as a result of damped oscillation. The applied brake pressure for a given brake handle position is determined statically, before the train starts moving. It isn't reset, while the train is moving. While this pressure would not have locked the wheels in normal circumstances, it might if the effective load on the truck were reduced during a damped oscillation. This effect might not be noticed but would put successive flat spots on the wheels. This could be interpreted as excessive wear. This is just a potential solution in search for an appropriate problem. Still this potential cause should be considered among the usual suspects. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by heypaul on Fri Mar 14 21:27:55 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Fri Mar 14 20:36:56 2025. Your relation between your bike riding experience and the trucks on a subway car is very subtle and very insightful. Your analysis is beyond me, but I really respect your connections.What would be the usual suspects for the excessive wheel wear? Do you have any sense of where the MTA's people have been looking and whether they have found a cause and solution? |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Train Dude on Fri Mar 14 22:43:50 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by zac on Fri Mar 14 18:33:58 2025. If they were simply testing ATO braking with empty cars, the load weight sensor would set the braking to AW0 rates. To get to what you suggest, the car would have to be weighted or they would have to deliberately defeat the load weight sensor. |
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| (1640027) | |
Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Train Dude on Fri Mar 14 22:50:41 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Fri Mar 14 20:36:56 2025. When the car is weighted with weight stacks, the weight used is to simulate a fully loaded car, IIRC 270 people or 270 X 150 Lbs. Therefore the car would be operating within the actual design parameters. What you seem to be suggesting is that the car might be randomly over-weighted or improperly h designed. The former is not done but perhaps the 2nd is possible but unlikely |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Steamdriven on Fri Mar 14 23:18:46 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Fri Mar 14 22:43:50 2025. A standard anti-skid system can deal with that, it can adjust many times per second. They work on rate of deceleration and thus aren't confused by changing vehicle weight. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Steve B-8AVEXP on Sat Mar 15 08:46:39 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by LuchAAA on Fri Mar 14 20:11:30 2025. Reminds me of when Abbott trains were eight cars long on Saturday mornings. I'd be standing towards the southern end of the s/b platform at 42nd St. and would have to make a mad dash when the train stopped well short of that. Back then, I had no idea there was such a thing as stop marks for different train lengths. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Sat Mar 15 08:50:37 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Fri Mar 14 22:50:41 2025. There's a tendency to believe if a system is tested for stability at the extreme values for a certain parameter, then all intermediate points will also be stable. In this instance, braking with no load and maximum load. This assumption isn't necessarily true, when the system includes energy storage elements. There could be resonance points which could be excited at intermediate loading levels. These are usually damped out.One exception was the PCC car. I had plenty of experience riding them during the time I spent in Boston during the early 1960's. Passengers loading and unloading would rock the PCC's from side to side. This was especially evident at Park St for cars going to Scollay Square and beyond. Both sides opened on this track. Many cars would completely unload and load. Operators would have to wait for the rocking to subside before proceeding. One effect that I did not mention is that braking will place more weight on the front truck and reduce the weight on the rear truck. The effect is similar in an automobile. If you brake hard, you will notice that the front end dips. This is due to braking deceleration is applied at the wheels but the car body wants to keep moving. The car body's continued forward motion will make it try to pivot at its connection to the axle. The magnitude of this effect depends on the location of the car body's center of mass. In particular it's proportional to the ratio of the CM's height above the track over its distance from the front axle. I would not think this should be a factor, given car body dimensions. I think it would be greatest when there is no passenger load. Then the weight of the roof mounted AC units would raise the CM's height. Again, just a solution looking for an appropriate problem to solve. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Train Dude on Sat Mar 15 10:30:26 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Stephen Bauman on Sat Mar 15 08:50:37 2025. So you are suggesting that it's AW1 or AW2 loads that are causing excess wheel wear? I think that when the cause is revealed, it will be far more basic but time will tell. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Train Dude on Sat Mar 15 10:33:37 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Steamdriven on Fri Mar 14 23:18:46 2025. A standard anti-skid system will prevent what, exactly? |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Sat Mar 15 11:04:08 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Sat Mar 15 10:33:37 2025. A standard anti-skid system will prevent what, exactly?Flat spots on wheels. |
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Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem? |
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Posted by Stephen Bauman on Sat Mar 15 11:31:10 2025, in response to Re: R Train May Run 8 Cars Instead of 10...Re: Is There an Update on the R160's Wheel Wear Problem?, posted by Train Dude on Sat Mar 15 10:30:26 2025. I was trying to apply some general engineering principles to explain how wheels could momentarily lock. Momentary locking could explain excess wheel wear, if the locking periods were of extremely short duration.These principles apply but may account for less than 0.1% of wheel wear. I don't know. As I've said, I have a solution in search for a problem. It could be something as basic as a change in brake shoe material. We know the NTT brake shoes initially showed excessive wear because regenerative braking did not work. I have not seen recent accounts of brake shoe wear problems. Perhaps the brake shoe wear solution just substituted excess wheel wear. Who knows? We will have to wait until NYCTA announces a cause. I hope that announcement will be more honest than their hiding brake failure as the cause of the Williamsburg Bridge collision. |
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