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Re: Canarsie CBTC |
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Posted by RonInBayside on Wed Jun 15 18:47:57 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Wed Jun 15 18:29:04 2005. "Do you monitor my telephone and email? Do you have a privateinvestigator following me around to see who my contacts are?" Of course. You didn't realize that James Bond works for me (my secret identity is really M)? 8-) "Do you really think the best way to find out what the vendor is really doing is to walk into their front door (or web site) and ask them?" Yes, I do. You'll be amazed at what you can learn. By reaching the right people you can learn a lot more than what is on the website. To cite one stereotypic example, whenever I ask a French concern something I get a whole package express-mailed to me the next day and a business card of somebody who invites me to ask whatever I want. Now, you have to be cognizant that you are, in fact getting a biased view - clearly they will support their own product. And you can criticize it to your heart's content. But then at least you know what you're debating. "I don't know as much about it as I do about conventional signaling, but I'd be willing to bet I understand the technical details (not the stuff you read in the NYT) a lot better than you do. " Then start showing it. Instead of posting nonsense and letting Stephen and others take you apart with ease (and I know enough to be able to judge that you were not competitive in those exchanges) do a little research, make a couple of phone calls and go for it. That going to hurt you any? Wreck your pitching arm? Drive you to seek confession from your priest? And stop taking this so personally. Yes, I'm criticizing your approach to this. Get over it. Better yet, present what you've learned. If you want to "show me up" in the process, great. I'll take it cheerfully. |
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Re: Canarsie CBTC |
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Posted by Jeff H. on Wed Jun 15 18:57:09 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Wed Jun 15 18:47:57 2005. Well, like Selkirk I have "sources" but I'm not about todisclose all of it. And I'm not retired, unemployed, or otherwise in possession of large quantities of spare time with which to call vendors and solicit information. I do, however, have enough time to find out what is actually happening in the field, as opposed to the front office. |
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Re: Canarsie CBTC |
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Posted by SelkirkTMO on Wed Jun 15 19:01:53 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Wed Jun 15 18:57:09 2005. Thanks, buddy ... I *tried* to "play" but got bored with it. As you do, I know the score, probably from different people, but nonetheless from people who work *FOR* the VENDOR ... I *praise* you for your fortitude in even arguing, I gave up a while ago when my own "suggestions" were ignored. Hey ... nobody wants to hear it until it's time for us to tell our stories AFTER the wreck. :(I *owe* you a beer, buddy! :) |
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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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Re: Canarsie CBTC |
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Posted by RonInBayside on Wed Jun 15 19:02:29 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Wed Jun 15 18:57:09 2005. "Well, like Selkirk I have "sources" but I'm not about todisclose all of it." OK, fine. :0) "And I'm not retired, unemployed, or otherwise in possession of large quantities of spare time with which to call vendors and solicit information." I researched and codesigned the "Ride and Seek" subway game prototype while I was in the midle of a med school rotation requiring 80 hours per week of my time. Don't give me bullshit excuses. If you have enough time to post here you have enough time to do a look-up. "I do, however, have enough time to find out what is actually happening in the field, as opposed to the front office. " OK. So go and do it and present it here. |
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Re: Canarsie CBTC |
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Posted by SelkirkTMO on Wed Jun 15 19:06:38 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Wed Jun 15 19:02:29 2005. Thank you for indictaing PRECISELY why *I* had to bow out of this, and other even deeper technical conversations. Unca Jeff works nearly the same number of hours *I* do in his craft and while I enjoy coming to hang out here and play among friends, *I* certainly don't have the time to document things unless they're on the first page of a google search these days. But I always have time for a quick drop-in, a quick one-liner and it's back off to business again. Jeff's got a similar problem of "sure wish I *COULD* get into this" ...One of the NICE things about a 40 hour week is that you DO have time to get bored and hit the boards. Some of us however work 80 hour weeks and then some. Do the math. Enjoy the comeraderie of someone who'd rather come hang out HERE than just GO to bed. Heh. MY excuse is that the compiler's going to chew on a rewrite for 5 minutes, might as well spend it HERE. :) |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Wed Jun 15 19:11:16 2005, in response to Re: Canarsie CBTC, posted by SelkirkTMO on Wed Jun 15 19:06:38 2005. "Unca Jeff works nearly the same number of hours *I* do in his craft and while I enjoy coming to hang out here and play among friends, *I* certainly don't have the time to document things unless they're on the first page of a google search these days. But I always have time for a quick drop-in, a quick one-liner and it's back off to business again."That's fine - except that this doesn't exlain or justify the obvious mistakes in the posts regarding CBTC. Mistakes big enough to drive a truck through. "I'm busy," "I have contacts but I won't mention them," etc. are fine until you try to post authoritatively and can't. Then they become just nice ways of admitting you don't know what the hell you're talking about. I gave Jeff an invitation. It's up to him. |
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Re: Canarsie CBTC |
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Posted by SelkirkTMO on Wed Jun 15 19:26:58 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Wed Jun 15 19:11:16 2005. I have "contacts" on a number of things too and the REALITY is among transit people that FEAR is the rule of the day. You might recall an incident regarding a MOD trip and "an historical event" planned to occur. STUPID me, I made the mistake of coming HERE and saying something I wasn't told NOT to. It STILL screwed up the lives of others and I had to relent in order to try to limit the damage to others that might very WELL have cancelled the trip.Despite my efforts, a *LOT* of people got into serious trouble as a result of my loose lips. I'm resolved, like Unca Jeff to NEVER put INNOCENT people who tell us something NOT for public consumption what we were told. Sorry guy - I hope YOU AND I at least have enough respect for each other to understand as to what Unca Jeff is *NOT* saying ... if we were dealing with the "private sector" here, then perhaps those "in charge" would be willing to sit back and wonder if anyone else had a more "profitable idea" ... in GOVERNMENT, it's shoot the messenger and anyone who MIGHT have had contact with them. If you've EVER done "civil service" then you might understand what I mean here. But I *know* Unca Jeff PERSONALLY, I *KNOW* his involvement in *THIS ALL* and I *KNOW* why he can't speak "truth" ... sorry to say, that's what happens when you have chickenshits for "leaders" who go AFTER those who can't see the emperor's clothes. Jeff needs NOBODY to speak on his behalf ... but rest ASSURED that he *KNOWS* the realities, I've heard them all MYSELF and BOTH of us have been told "keep it deep hat." *OH* if only we could flap out gums about what we REALLY know. But we'd be betraying confidences of our OWN close friends. Don't be dissing the boy though - he *KNOWS* the score, even more so than *I* do. Same for the OTHERS who are still *IN* the system telling the *SAME* story. This CBTC implementation is "666" ... :( |
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Re: Canarsie CBTC |
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Posted by tracksionmotor on Wed Jun 15 22:47:28 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Thu Jun 9 22:07:43 2005. LIRR runs ATO...I've been modifying the 'antenna shields' because they have been falling off. Say you have five hundred miles ofstraight track...how many inductive transponders do you need if trains run fiftey mph pace? How many times must signals interrogate the trainset? NJT has no trips but batch of T/Os got caught running red lights. Point is system needs a limited number of comms...T/O can be tweaked for response at any time period by MCC without comm into system. Yes, conventional RR block system modified for comm. CBTC cannot have dead spots, period. I know RF systems from DC to light. CBTC inductive pickup at say every 200 feet will work perfectly...trainset is roughly 500 feet long. Don't talk RF propagation to me...the 'sticker box RF comm system' that NYCTA will use is like the cheapo RF TV remotes....and subject under law to any and ALL interference as an unlicensed part 15 user. That's right...NYCTA will use an unlicensed Part 15 system on ungaurded frequencies. Say I key up on 440 mHz FM with five watts and second harmonic of ELP level coincides with trainset comm links. Something happens, trainset comm system huntsa for another frequency (IF system works that way) with dead comm BIE trainset. Whos fault is it? NYCTA, trainset manufacturer, vendor or me? On any frequency at any time of any mode of any power level, I am the primary user as licensed by the FCC as a commercial radio operator. TA/trainsets...just cheap CB. Think. CI peter |
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Re: Canarsie CBTC |
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Posted by tracksionmotor on Wed Jun 15 23:10:56 2005, in response to Re: Canarsie CBTC, posted by Alex L. on Wed Jun 15 12:29:30 2005. AND you have done verrry well. CI peter |
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Re: Canarsie CBTC |
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Posted by Jeff H. on Wed Jun 15 23:50:00 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Wed Jun 15 19:02:29 2005. OK. So go and do it and present it here.I think I've already gone over this several times. Basically it comes down to: 1) CBTC is the "only alternative". Other potential technologies are not being evaluated. 2) CBTC is a tremendous 'culture shock' to the way NYCT understands signaling. Strategies to bypass that culture shock by bringing in "untainted" outsiders with a "fresh view" on signaling have not been as successful as hoped, because in the end, its still all about signaling and safely controlling train movements, which is a craft distinct from ATM machines, web browsers and (yes SB) industrial controls. Although there are some very qualified people involved with trying to make CBTC work, on the whole, the team just doesn't have the "voodoo". Unless you've actually worked in a technical field and experienced good system installs and bad installs, I doubt you can truly understand what I mean by that. 3) This implementation is seriously behind schedule. It has over-run all of its milestones faster than Ed Luciano's train through the Malbone Street cut. |
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Re: Canarsie CBTC |
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Posted by tracksionmotor on Thu Jun 16 00:32:07 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Wed Jun 15 23:50:00 2005. Just one of the many reasons why I've left TA......TA assigns you to a task irregardless of backgound. Never ever any possibility I would ever get to do anything close to thirty years of experience. NYCTssignaling remains to this day the works of 'Morse and Edison.' Lucky souls got a taste of Tesla that brought concept of IRT into reality. the Queensboro Bridge is a reminder of the skilled souls who put 1904 together. Working ATO/ATS/ATC/CBTC.....impossible. Painting yellow lines with water soluable paint....overtime. Totally retarded. |
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Re: Canarsie CBTC |
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Posted by vengence on Thu Jun 16 00:58:39 2005, in response to Re: Canarsie CBTC, posted by SelkirkTMO on Wed Jun 15 19:26:58 2005. LOL...Dammit.. KIRK! I hate it when you tell it so "as a mater of fact" like...! And I hate it WHEN IM RIGHT about something! CBTC is..a failure... The PROBLEM is..they should have ironed out ALL the buggs on the Smith st express tracks FIRST..THEN install it on the L Line. I mean..what was the sense of installing it on the Culver line if it was only going to collect dust? |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Thu Jun 16 09:10:27 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Wed Jun 15 23:50:00 2005. "I think I've already gone over this several times"No. You've gone over your prejudices and misconceptions without demonstrating that you know very much about CBTC in general and zero about Siemens. You're capable of a marvelous discourse about conventional signalling, and even though I can't follow all of it, I have found myself looking up things just to understand you better. You should take that as a compliment, because it is. That's why I also express fristration with your insistence on degenerating to your discussion to ignorant nonsense when it comes to CBTC - all because you're too intellectually lazy to look up anything (or you're afraid to learn something new??). "CBTC is the "only alternative". Other potential technologies are not being evaluated." After you fill in your own understanding of CBTC (hhey, and ours too, OK?) then you can intelligently discuss the alternatives. Not before. And you have not done that yet. "CBTC is a tremendous 'culture shock' to the way NYCT understands signaling. Strategies to bypass that culture shock by bringing in "untainted" outsiders with a "fresh view" on signaling have not been as successful as hoped," You're OK so far. Change has that affect on people. Good management knows how to deal with that. If you want to read a classic business case on culture shock check out the Harvard Business Review from a few years ago - they have a great article on what happened at Volkswagen's plant in Mexico City. "because in the end, its still all about signaling and safely controlling train movements, which is a craft distinct from ATM machines, web browsers and (yes SB) industrial controls." False statement, and incredibly ignorant on your part. Pure bullshit with nothing -ZERO - to support it except your prejudice towards recent technologies. It's really about the willingness of rank and file to learn how to deal withnew technology - period. There is TWU and its leadership with their heads up their rear-ends, there's the TA with its sometimes overbearing and authoritarian management style (so its a vicious circle) and then there's Siemens stepping into the middle of it all. "Although there are some very qualified people involved with trying to make CBTC work, on the whole, the team just doesn't have the "voodoo". If you are referring to conflict between Siemens and NYCT personnel, you may have a point. But that is a mansagement problem, not a technology problem. How is Siemens' rlationship with RATP in France? How does the degree of culture shock vary there? It might be interesting to compare the two. "Unless you've actually worked in a technical field and experienced good system installs and bad installs, I doubt you can truly understand what I mean by that." I know exactly what you mean, because I've seen that in IT (both commercial and medical IT). I also was lead consultant recently on an NYC project involving introduction of new technology for healthcare and one of the biggest challenges was getting different organizations to work together and buy into thenew concepts. The nuclear power industry is a place where new technologies (such as computers in the control rooms) were resisted because of concerns in mission-critical systems. Ditto for commercial jetliners - remember when flight engineers were replaced by Fuel Management Systems. An Airbus A300crashed early on because of bugs in the software; most recently an A340 nearly crashed. But overall the technology works well (and Boeing has not had a problem with it). |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Thu Jun 16 09:14:53 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Wed Jun 15 23:50:00 2005. 2) ...in the end, its still all about signaling and safely controlling train movements, which is a craft distinct from ATM machines, web browsers and (yes SB) industrial controls....The craft for controlling train movements is not changed under CBTC. There are N trains to be controlled. At time T, each of the trains has position: x1(T), x2(T),..., xN(T); each of the trains has velocity: v1(T), v2(T),..., vN(T). These parameters are transmitted to the control system. The control system issues commands to the trains for v1(T+Δt), v2(T+Δt),..., vN(T+Δt) which are transmtted to the trains. The craft or algorithm by which these commands are determined from these parmaters has not been changed. What has been changed is how x1(T), x2(T),..., xN(T) and v1(T), v2(T),..., vN(T) are measured and how these parameters and commands v1(T+Δt), v2(T+Δt),..., vN(T+Δt) are transmitted between the control system and the trains. I had supposed the problems with the Canarsie Line's CBTC implementation were limited to the transmission between the trains and the control system. You have hinted there may also be problems in measuring the state parameter variables. There may well be problems in how Siemens translated the control algorithms. There should not be any because the company Siemens purchased has been in that business for eons. However the project has not progressed far enough to evaluate that part. |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Thu Jun 16 09:17:11 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Thu Jun 16 09:14:53 2005. Very nicely stated on your part. |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Thu Jun 16 09:44:50 2005, in response to Re: Canarsie CBTC, posted by tracksionmotor on Wed Jun 15 22:47:28 2005. Don't talk RF propagation to me...the 'sticker box RF comm system' that NYCTA will use is like the cheapo RF TV remotes....and subject under law to any and ALL interference as an unlicensed part 15 user. That's right...NYCTA will use an unlicensed Part 15 system on ungaurdedfrequencies. Say I key up on 440 mHz FM with five watts and second harmonic of ELP level coincides with trainset comm links. Something happens, trainset comm system huntsa for another frequency (IF system works that way) with dead comm BIE trainset. Whos fault is it? NYCTA, trainset manufacturer, vendor or me? On any frequency at any time of any mode of any power level, I am the primary user as licensed by the FCC as a commercial radio operator. TA/trainsets...just cheap CB. Clearly, a receiver is badly designed, if a legal signal can overpower the its RF or IF stages. This has not proven to be a problem for the more than 15 million 802.11 spread spectrum systems currently in use in the US. Spread spectrum is not like most of the RF applications that you have encountered with regard to its suseptibility to RF interference. It is used by the military for battlefield communications because it is far less likely to be jammed or have its security compromised than most other forms of RF communications. Spread spectrum systems operate reliably in the presence of more powerful wide and narrow band signals even when there is spectral overlap. Those are the properties of the type of RF link that is planned for CBTC. The best (or worst depending on one's perspective) jamming signal is not necessarily a strong one. It is one that mimics the characteristics of the desired signal. Something about correlation detection and Wiener filtering. That's why AC powerline arcing gives spread spectrum problems. Primary, legal use of the assigned frequencies by radio amateurs should not. |
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Re: Canarsie CBTC |
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Posted by H.S.Relay on Thu Jun 16 17:41:15 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Tue Jun 14 21:57:22 2005. 142s _DO_ have tachs on the axles. |
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Re: Canarsie CBTC |
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Posted by H.S.Relay on Thu Jun 16 17:48:46 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Sat Jun 11 10:17:57 2005. So does ordering replacement relays at $60 million per room.Okay, so add an extra $60 million to every interlocking on Canarsie, since they are all relay-based interlockings. Where's the savings? somebody like you who puts cardboard covers over your lenses So Ron, as someone responsible for his own education, what qualifies you to say Jeff is on the wrong track about the OSMES? Are you saying that you have concrete proff that everything is going just fine with CBTC train positioning? |
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Re: Canarsie CBTC |
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Posted by Jan K. Lorenzen on Thu Jun 16 18:04:18 2005, in response to Re: Canarsie CBTC, posted by tracksionmotor on Wed Jun 15 02:05:39 2005. Reach behind the dash and pull the bulb. Add sawdust to the differential. Three raw eggs in the radiator. :) |
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Re: Canarsie CBTC |
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Posted by tracksionmotor on Thu Jun 16 22:03:57 2005, in response to Re: Canarsie CBTC, posted by Jan K. Lorenzen on Thu Jun 16 18:04:18 2005. I've found plenty of NYCTA trainsets where indication bulbs were pulled to belay investigation. The BIG problem spurts out when theT/O indication is inoperative and the train can't go. New Tech hides nothing....all can be revealed on a download. CI peter |
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Re: Canarsie CBTC |
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Posted by tracksionmotor on Thu Jun 16 23:48:22 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Thu Jun 16 09:44:50 2005. I am well aware of what spread spectrum is having worked in the pioneering fields. Spread spectrum is multifold based upon software...it can simply spread out data comm to prevent intrusion or it can seek out unoccupied channels and packet reflect in the event of interference like TOR. My concern is of receiver swamping...it doesn't have to be intentional jamming. Yes, 802.11 users are happyusers BUT my experience tells me railcomm needs guarded channels. Frankly, 802.11 is part 15 hobbyists. When it comes to safety sensitive control systems...gimme the twisted pair anytime. Placing RF taggers of 802.11 on boxcars is OK...using it for NYCCBTA is another matter. I've worked the HF systems...Sun...transceivers scan and tweek HF spectrum 24/7 so when user picks up telephone handset the link and viable unoccupied frequencies have already been set up. Trust a trainset to do this reliably for control systems? Go ask Santa Claus!!! CI peter |
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Re: Canarsie CBTC |
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Posted by Jeff H. on Fri Jun 17 02:29:52 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Thu Jun 16 09:14:53 2005. The craft for controlling train movements is not changed under CBTC. There are N trains to be controlled.... That's a mathematical model you presented (and not clear if you mean to be in discrete or continuous time?) and isn't remotely close to what the average person would understand from the word "craft". In all your years in industrial controls, did you not once find a real-world situation that departed from textbook analysis? |
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Re: Canarsie CBTC/RF |
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Posted by Jeff H. on Fri Jun 17 02:41:40 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Thu Jun 16 09:44:50 2005. Stephen,He's talking about "front end overloading", a widely-understood problem in RF communications. Even when spread-spectrum is used, as in 802.11, it is still a relatively narrow band. E.g. 802.11b and g are between 2.412 and 2.462 GHz. I'm pretty sure most designs have one RF amp for that entire band, and then do the frequency-hopping on the receive side by changing local oscillator frequencies. If you can get enough RF energy within that band delivered to the antenna, it will either drive the RF amp into clipping, or the AGC will kick in and reduce the amplitude of the real signal that is being delivered to the IF stage. Obviously you can design around that by using very good shielding, and having large dynamic range in the RF circuits. But it is certainly possible. I have seen commerical-grade 802.11 systems degrade and even fail to associate with the AP from proximity to strong RF sources, or even a large amount of aggregrate RF energy, e.g. when too many people are running their own private 802.11 networks in close quarters. |
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Re: Canarsie CBTC |
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Posted by Jeff H. on Fri Jun 17 03:52:02 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Thu Jun 16 09:10:27 2005. After you fill in your own understanding of CBTC (hhey, and ours too, OK?) then you can intelligently discuss thealternatives. Not before. And you have not done that yet. Yeah I have numerous times but you weren't paying attention. In a nutshell, this is my understanding of how CBTC works, from memory, without quoting from things on the internet: Railway signaling (as it pertains to the NYC transit system, so we're not talking about things like hump yards and rock slide detection) is concerned with two primary things: safe spacing between trains and "interlocking" (the coordination between the safe movement of trains and the movement of switches). CBTC does not address interlocking, so let's move on. There are numerous approaches to maintaining safe distance between trains. We'll consider only those systems that provide Positive Train Control, e.g. the trip stop mechanism currently used, as opposed to those which rely solely on the operator's observance. In order to keep trains separated, it is necessary to determine their position. All signal systems to date have used track circuits to do this. I will not explain what a track circuit is as I think it is common knowledge. In addition to knowing a train's position, it is necessary to be able to make some statement about its speed, and its maximum safe braking distance at that speed. In a wayside ABS such as used in NYCT, determination of position can only be made at the granularity of the track circuit boundaries (the insulated joints). Likewise, speed through a block must be assumed to be the maximum fleet speed (this approach works because NYCT does not mix equipment with radically different top-end speeds in service as a mainline RR might), OR if a "timer" is used, then speed has been demonstrated to be some lesser number. Commands to the train crew as well as enforcement commands (stop arm up) likewise can only be transmitted at track circuit boundaries. In NYCT's ABS system, the variables are very simple and in fact reduce to booleans. All of the logic is performed in the wayside signal locations. There is no car-borne equipment except for the trip cock. Interoperability concerns are limited to the position of the trip cock on the car. Another system which has been successfully used in thousands of miles of track, both mainline and transit, is Automatic Speed Control with coded track circuits. In this system, the wayside logic can establish one of a fixed set of allowable speeds through a block. This command is transmitted through a very simple and robust manner: by modulating the track circuit energy at a very low frequency (generally 1-7 Hz). The car-borne equipment is relatively simple and consists of an inductive loop which picks up the modulation, some passive filter components, some relays, and a speedometer. Since the train is responsible only for measuring speed, not position, the speedometer accuracy is not critical. With ASC, although the commands are transmitted at discrete points along the railroad (again, the track circuits), they are being transmitted continuously, as opposed to the intermittent commands of a wayside color light system with trips. ASC provides positive enforcement of speed and therefore the wayside system "knows" the speed of a train through each block, and can allow following trains to "creep up" without having to add a bunch of shorter blocks and "station timers". ASC achieves good cross-vendor interoperability because the "protocol" is so simple one can analyze it with a Simpson 261 multimeter. Many people have a mental equation in their heads that OLD SCHOOL SIGNALS == RELAYS That isn't the case. Systems have been installed for several decades now which use microprocessors to replace 99% of the relays in both wayside ABS, interlocking, and coded track circuit ASC systems. So next time somebody gives "eliminating relays" as an advtange of CBTC, keep that in mind. The paradigm shift of CBTC is to make the train responsible for knowing not only its speed, but also its position. There are a number of technological ways to do that, but they all boil down to measuring elapsed distance (and with a little d/dt, speed) and periodically checking that against fixed beacons. Another key element of CBTC is that the train estimates its own safe braking distance. This requires tight integration with the propulsion and braking packages (and therefore makes retrofit of "legacy" equipment difficult). Under CBTC, the train is in constant communication with a wayside control element. This communication is digital and follows a complex protocol with many thousands of lines of code to drive it. Again, there are many possible technologies which can be used in the communications link and, as of 2005, no consensus as to what will become the standard, in terms of the physical interface, the data link interface, or the network interface. The wayside zone controller maintains communication with adjacent zone controllers and is able to hand-off as the train passes from zone to zone. The controllers constantly monitor the position, speed and braking profile of all trains and constantly transmit commands back to the train giving their allowable speed. The trains enforce the speed either with speed control (motor cutoff and penalty applications) or completely automatic operation. The elegance of CBTC is that it removes the intermediate layer of track circuit and gets right down to the essentials: speed, position, braking. In theory, this approach could allow trains to operate as quickly and as closely together as is safely possible, without any loss of efficiency from the signal system. Another advantage of CBTC is the reduction in maintenance of wayside elements. Although CBTC has plenty of wayside equipment, none of it is in the roadbed with trains passing over it (well, that's a stretch, but basically correct). That's the theory of CBTC. [CBTC does not provide interlocking, and I have not discussed how the CBTC system interfaces with interlocking systems] People have this idea that Canarsie trains will be flying along at top speed only a few hundred feet apart, and that tph capacity will be greatly increased. Unfortunately, that is not the reality of the Canarsie CBTC implementation, and I mean yes, even when and if it is working 100% according to spec. Basically, on Canarsie, the track is broken up conceptually into a number of "virtual blocks" which are fixed in location, and are comparable to the existing blocks in size. You essentially are getting exactly what ASC with coded track circuits gives, minus the insulated joints (and impedance bonds, since single-rail coded track circuits don't work out so great), plus a lot of very complicated and proprietary wayside and car-borne equipment. Now, I say to you, what's the relative value proposition? Will the maintenance savings on the insulated joints outweigh the higher install cost of CBTC, the need to hire more expensive consultants and specialists, and the future headaches of incompatibility? |
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| (99848) | |
Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 07:23:09 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Fri Jun 17 02:29:52 2005. That's a mathematical model you presented (and not clear if you mean to be in discrete or continuous time?) and isn't remotely close to what the average person would understand from the word "craft".I'm shouldn't doubt that the average person might not understand his "craft" from my mathematical model.:=) However, I submit that it is accurate in this instance. All it says is that the control system knows the speed and location of each train within its jurisdiction and issues commands to each train as to what the desired speed should be. I think you have said essentially the same thing in a subsequent post. In all your years in industrial controls, did you not once find a real-world situation that departed from textbook analysis? Many textbooks will make simplifications to illustrate only one or two principles in an example. If your question had been: have I ever encounted a situation wherein Maxwell's equations or Newton's laws were violated, then the answer is no. Have you encountered such situations? |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 07:53:51 2005, in response to Re: Canarsie CBTC, posted by Jeff H. on Fri Jun 17 03:52:02 2005. "The paradigm shift of CBTC is to make the train responsible forknowing not only its speed, but also its position. There are a number of technological ways to do that, but they all boil down to measuring elapsed distance (and with a little d/dt, speed) and periodically checking that against fixed beacons." Or using GPS above ground, which is now accurate enough for use in transit (obviously it's a little difficult to reach a satellite from a tunnel). "In theory, this approach could allow trains to operate as quickly and as closely together as is safely possible, without any loss of efficiency from the signal system." And in practice it actually does exactly that. "People have this idea that Canarsie trains will be flying along at top speed only a few hundred feet apart, and that tph capacity will be greatly increased." I don't have that idea in my head. I do have the idea that there will be some improvement from the outset, with additional improvement as CBTC operation is tweaked. That, plus the reduction in maintenance and reliance on equipment which only one compasny in the US is capable of manufacturing anymore. CBTC is far cheaper to maintain than the type of equipment used now. It isn't just insulated joints; it's the relays that run to $60 million worth of equipment to control just 2,000 feet of route (Chambers St as example). Your post still doesn't tell me what Siemensis doing. Worse, I just showed you that you're ignoring whole topics within the debate. So not only are you incompentent in CBTC, you're also a liar. |
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Re: Canarsie CBTC/RF |
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Posted by Stephen Bauman on Fri Jun 17 08:35:38 2005, in response to Re: Canarsie CBTC/RF, posted by Jeff H. on Fri Jun 17 02:41:40 2005. He's talking about "front end overloading", a widely-understood problem in RF communications...Obviously you can design around that by using very good shielding, and having large dynamic range in the RF circuits. But it is certainly possible.I'm happy that at least one person with "real world railroading" experience thinks that this might not be an insurmountable problem. I have seen commerical-grade 802.11 systems degrade and even fail to associate with the AP from proximity to strong RF sources, or even a large amount of aggregrate RF energy, e.g. when too many people are running their own private 802.11 networks in close quarters. I should think some form of failure mode analysis would be appropriate here. If the RF sources or aggregate RF energy from many 802.11 users resulted in front end overload, then the suggestions you made above would be appropriate. OTOH, two or more AP's might be using the same seed for DSSS or FHSS and interfering with one another. This is common because most wi-fi users don't bother changing their parameters from the default factory settings. However, this should not be a realistic scenario for a NYCT installation. There just are not that many underground AP's. |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 08:39:56 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 07:53:51 2005. But you can prove me wrong if you make an effort (HINT: It's called research).If you do, I'll eat my hat! |
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Re: Canarsie CBTC/RF |
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Posted by RonInBayside on Fri Jun 17 08:43:58 2005, in response to Re: Canarsie CBTC/RF, posted by Stephen Bauman on Fri Jun 17 08:35:38 2005. So underground there really isn't a problem. Above ground, on the elevated lines, there might be, given the close proximity New York's Els come with regard to buildings. Hence the mitigation schemes.Modern elevated lines in other cities were built with more buffer between them and where people live and work. |
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Re: Canarsie CBTC |
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Posted by David of Broadway on Fri Jun 17 08:50:59 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 07:53:51 2005. CBTC is far cheaper to maintain than the type of equipment used now. It isn't just insulated joints; it's the relays that run to $60 million worth of equipment to control just 2,000 feet of route (Chambers St as example).I see you don't bother to read his post before "responding" to it. Why am I not surprised? |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 08:54:14 2005, in response to Re: Canarsie CBTC, posted by tracksionmotor on Thu Jun 16 23:48:22 2005. My concern is of receiver swamping...it doesn't have to be intentional jamming.Thanks for the clarification. Mr. Jeff H said the same thing in his reply. He also presented some possible solutions for addressing this problem. gimme the twisted pair anytime It's pretty difficult to run a twisted pair between a moving train and wayside equipment. :=) Yes, 802.11 users are happy users BUT my experience tells me railcomm needs guarded channels Wherefore is railcomm different from all other comms? :=) |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 08:55:19 2005, in response to Re: Canarsie CBTC, posted by tracksionmotor on Thu Jun 16 22:03:57 2005. I've found plenty of NYCTA trainsets where indication bulbs were pulled to belay investigation.Isn't there a lamp test button? |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 09:11:22 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 07:53:51 2005. Or using GPS above ground, which is now accurate enough for use in transitGPS is not sufficiently accurate by itself for use in transit. Transit needs identification between adjacent tracks. GPS cannot supply it. |
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Re: Canarsie CBTC/RF |
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Posted by Stephen Bauman on Fri Jun 17 09:21:28 2005, in response to Re: Canarsie CBTC/RF, posted by RonInBayside on Fri Jun 17 08:43:58 2005. So underground there really isn't a problem.Underground has a different problem - RF propagation in the tunnels. Above ground, on the elevated lines, there might be, given the close proximity New York's Els come with regard to buildings. I have not looked at recent hotspot maps. However, I'd think for now that this should not be much of a problem considering that the El's are outside major business areas. |
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Re: Canarsie CBTC |
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Posted by Railman718 on Fri Jun 17 09:37:38 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Fri Jun 17 08:55:19 2005. Yes there is a lamp test button as part of your "short" pre-trip inspcetion you have to press that button to see if those buttons are working as desigend on the R142's. |
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Re: Canarsie CBTC |
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Posted by Terrapin Station on Fri Jun 17 10:40:02 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 08:39:56 2005. If you do, I'll eat my hat!You don't wear hats. How about you'll leave SubChat for good if he can prove you wrong? |
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Re: Canarsie CBTC/RF |
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Posted by RonInBayside on Fri Jun 17 13:10:02 2005, in response to Re: Canarsie CBTC/RF, posted by Stephen Bauman on Fri Jun 17 09:21:28 2005. "Underground has a different problem - RF propagation in the tunnels. "Yes, absolutely. Thank you! "I have not looked at recent hotspot maps. However, I'd think for now that this should not be much of a problem considering that the El's are outside major business areas." In general that seems reasonable, but as hot spots grow in number and get more spread-out (esp. the home-based networks) it may become an issue. In Chicago by contrast, the elevated trains run smack in the middle of the business district. |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 13:11:16 2005, in response to Re: Canarsie CBTC, posted by Terrapin Station on Fri Jun 17 10:40:02 2005. Sorry. You're stuck with me. As you grow and become more mature that will be less of a problem. |
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Re: Canarsie CBTC |
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Posted by Terrapin Station on Fri Jun 17 13:13:56 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 13:11:16 2005. I'm not stuck with you at all. I can choose whether or not to read your posts. But the fact remains that you don't wear hats and so your promise in that previous post is worthless.I'm also very mature. I don't beat up foster parents anymore. (and don't say that it's because I don't have foster parents anymore. It's because I'm mature now!) |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 13:18:33 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Fri Jun 17 09:11:22 2005. Yes, you're right. With accuracy of plus/minus 15 feet, GPS is good enough to keep trains on the same track away from each other, but not good enough to properly govern two adjacent tracks by itself. It would need to work with an adjunct. |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 13:20:22 2005, in response to Re: Canarsie CBTC, posted by Terrapin Station on Fri Jun 17 13:13:56 2005. "But the fact remains that you don't wear hats"How do you know? You have seen me once and I may not have worn a hat that day. In fact, I wear a baseball-tpe cap once in a while that I received as part of the 207 St shop open house on Sept 9, 2001. |
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Re: Canarsie CBTC |
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Posted by Terrapin Station on Fri Jun 17 13:25:29 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 13:20:22 2005. Funny, I got a new hat that day also. My dad and I drove out to Milwaukee to see a Brewers came and I bought a Brewers hat after the game was over. But I got rid of it a while ago. It didn't like it so much. |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 13:35:06 2005, in response to Re: Canarsie CBTC, posted by Terrapin Station on Fri Jun 17 13:25:29 2005. I usually favor light-colored hats (because they reflect sunlight better on hot days). The 207 St Shop hat is dark, but I like it anyway - it's a special hat from a special place! |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 13:49:28 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 13:18:33 2005. Yes, you're right. With accuracy of plus/minus 15 feet, GPS is good enough to keep trains on the same track away from each other, but not good enough to properly govern two adjacent tracks by itself.No, Mr. Jeff H was correct in asserting that fixed beacons were required for determining position. I merely pointed out that you were wrong in your assertion that GPS could be used as an alternate. Does that make you a liar or an ignoramus? |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 13:52:52 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Fri Jun 17 13:49:28 2005. "No, Mr. Jeff H was correct in asserting that fixed beacons were required for determining position."Why would GPS not be appropriate (other than inadequate resolution)? |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 13:55:50 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Fri Jun 17 13:49:28 2005. Neither. It means you didn't understand my question, and chose not to ask me about the source of your confusion.Jeff's wrong, by the way. |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 14:09:42 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 13:52:52 2005. Why would GPS not be appropriate (other than inadequate resolution)?I think you mean accuracy. Why would any technology be appropriate in an application, if that technology provided innacurate data within the context of the the accuracy required for that application? |
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Re: Canarsie CBTC |
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Posted by Jeff H. on Fri Jun 17 16:45:42 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 07:53:51 2005. That, plus the reduction in maintenance and reliance onequipment which only one compasny in the US is capable of manufacturing anymore. CBTC is far cheaper to maintain than the type of equipment used now. It isn't just insulated joints; it's the relays that run to $60 million worth of equipment to control just 2,000 feet of route (Chambers St as example). Now that conclusively proves that you either don't want to listen to other people's arguments, or you can't follow them. I went through the trouble of explaining why "eliminating relays" could not be legitimately argued to be an exclusive benefit of CBTC, and in the direct follow-up post, you bring up this argument again. It's like talking to the wall. Why don't YOU do some research and tell us the truth about the relative relay consumption among different signal technologies including CBTC. And there are at least TWO US manufacturers of conventional relays, for what it is worth: SAFETRAN and US&S (although US&S is in fact owned by a French company, there are still many English-speaking people employed in this country whom you can talk to). If the TA needs to order a replacement part for Canarsie's CBTC system, how many US manufacturers can provide it? you're also a liar. To claim that I'm a liar, you should demonstrate something which I said which I knew to be untrue. Having a different opinion than you does not make one a liar. And, BTW, if you would like to tell us all what Siemens is doing, please go ahead and do so. |
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Re: Canarsie CBTC |
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Posted by RonInBayside on Fri Jun 17 17:57:55 2005, in response to Re: Canarsie CBTC, posted by Stephen Bauman on Fri Jun 17 14:09:42 2005. "Why would any technology be appropriate in an application, if that technology provided innacurate data within the context of the the accuracy required for that application?"GPS does provide the necessary accuracy to be of some service. However, you were correct in that if you had two trains adjacemnt to each other, GPS' accuracy would be insufficient to keep them separated for purposes of say, switching tracks and so on. But youcould use it to keep trains separated on the same track. Your software would have to compensate for the error, though. I am not aware of GPS-supported CBTC systems in operation today. If indeed there are none, I would not say that I would endorse GPS' use on a revenue CBTC system such as New York's; I would support an experimental trial of a GPS supported CBTC system on a test track somewhere, to demonstrate its potential and its limitations. But the blanket assertion that GPS cannot be used at to support CBTC is nonsense. |
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Re: Canarsie CBTC |
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Posted by Stephen Bauman on Fri Jun 17 19:52:12 2005, in response to Re: Canarsie CBTC, posted by RonInBayside on Fri Jun 17 17:57:55 2005. you were correct in that if you had two trains adjacemnt to each other, GPS' accuracy would be insufficient to keep them separated for purposes of say, switching tracks and so on.CBTC does not handle switching. But youcould use it to keep trains separated on the same track. Your software would have to compensate for the error, though. The software has to get the following information from the train: position, speed and which track it is on. Just how will the train supply this information to the software? Also, the software wants the position data as some distance along the track from some reference point. The GPS data is latitude, longitude and altitude. A complete track map including curves and grades is necessary to convert between the two. Additional calculations, even if some wayside beacon were to tell the train which track it were on. I am not aware of GPS-supported CBTC systems in operation today. Ever wonder why? I would support an experimental trial of a GPS supported CBTC system on a test track somewhere, to demonstrate its potential and its limitations. How much of your own money will you put up, for the test? |
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