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| Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... (1134468) | |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Stephen Bauman on Wed Jan 25 23:16:39 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Dj Hammers on Wed Jan 25 20:39:09 2012. would efficiency rise to the point of surpassing efficiency gains provided by CBTC?If by "efficiency" you mean service level capacity, then CBTC provides no gain over a properly designed conventional signal system. The existing 14th Street Line's signal system was properly designed. If you want to increase service level capacity, you need to work on improving the trains' service acceleration and braking rates as well as improving their emergency braking rate. Ironically, the operating characteristics of the Multis and Bluebirds that once operated on the 14th Street Lines had the capability of operating at higher service levels than the current crop of "new technology trains" composed of R143's and R160's. The old stuff was also faster. The running time of the 14th Street Express between Lefferts and 8th Ave was less than the current running time for the A train between these same two points. The Multis also made more stops. |
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| (1134991) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 09:12:20 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Henry R32 #3730 on Tue Jan 24 23:09:17 2012. That's what they do in Japan for stock transfers. They put a work motor with all the different train stoppers/cab signaling up front so they can run on freight lines etc... |
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| (1134992) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 09:29:37 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Henry R32 #3730 on Wed Jan 25 19:17:01 2012. Of course it's possible. In Japan, they installed the current ATS-P on steam locomotives so they can run again in normal service hours. Of course, there's nothing ATO there.As for museum trains in Paris, the way they run them now is pretty much run the same way way as when they run regular trains in manual mode, following wayside signals. Since CBTC is linked with wayside signals and the train sensors on fixed blocks, they can run mixed with ATO trains. The only difference is since the museum trains don't have deadman or train stops (as in trip cocks) of any kind, they require two drivers in the cab, the second driver being the human deadman system. I don't think Paris will bring moving blocks to every line. They haven't even put ATO on the less busy lines. Museum trains can run on those lines then. |
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| (1134993) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 09:31:31 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Wed Jan 25 20:54:11 2012. We're talking museum trains in Paris here. NYCT rules don't apply. They have their own rules. |
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| (1134994) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 09:42:17 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Wed Jan 25 22:31:09 2012. 1. CBTC offers capacity that NYCT cannot achieve with fixed block signalling.A moving block system does not require CBTC and CBTC can be implemented on fixed block systems too. 2. CBTC is cheaper than fixed block systems with wayside signalling. The only thing that will be cheaper for sure is the cost of parts/equipment needed for maintenance. |
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| (1134997) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Avid Reader on Thu Jan 26 10:22:20 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by BLE-NIMX on Wed Jan 25 01:05:23 2012. In a worse case sin air E O ,could a BL-20 , like on Staten Island be coupled to a set in need of Maintenance , taken over the LIRR to SunnySide, turned and taken over the Bay Ridge Branch to Coney Island Yard , avoiding all signals? avid |
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| (1134999) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by AEM-7AC #901 on Thu Jan 26 10:38:46 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Wado MP73 on Thu Jan 26 09:42:17 2012. A moving block system does not require CBTCExplain... |
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| (1135018) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 12:53:49 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by AEM-7AC #901 on Thu Jan 26 10:38:46 2012. Systems like ATACS in Japan do not have train control, just cab signaling and train protection.Come to think about it, the definition of the terms used is kinda vague. But to me, the Train Control part of CBTC means ATO capable. |
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| (1135023) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Thu Jan 26 13:03:47 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Stephen Bauman on Wed Jan 25 23:16:39 2012. If by "efficiency" you mean service level capacity,then CBTC provides no gain over a properly designed conventional signal system.Well that's an interesting metric of efficiency. I would assume 'efficiency' to be more of a bang for the buck type consideration, when you consider that CBTC allows trains to get far closer together than even the best fixed block system, at a far lower cost, then I would sure consider that to be more efficient. The existing 14th Street Line's signal system was properly designed. Unfortunately, numerous paramters have changed in the years since the Canarsie's fixed block system was designed, and it no longer was as 'efficient' as it previously was. |
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| (1135033) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Thu Jan 26 13:33:22 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Wado MP73 on Thu Jan 26 09:42:17 2012. A moving block system does not require CBTCThen how can it communicate where the block has moved to? CBTC can be implemented on fixed block systems Yes, Canarsie has been doing it for years. But at some point, you get rid of the fixed blocks and complete the switchover. Otherwise, there's not much of a point in implementing CBTC. The only thing that will be cheaper for sure is the cost of parts/equipment needed for maintenance. As a fixed block system has smaller and smaller blocks, the cost starts going up. NYCT, with its need to have trains running every 2-5 minutes on most lines, has a pretty robust signal system. Being able to get rid of such a "dense" system of fixed blocks should help the MTA reduce costs as the existing signals reach the end of their life cycles. |
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| (1135034) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Thu Jan 26 13:35:54 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Wado MP73 on Thu Jan 26 12:53:49 2012. CBTC doesn't mean ATO capable. It means that the trains are using wireless communication to let the rest of the system know where they are, how fast they're going, and also receive input on what speed they're allowed to travel at. However, once you have all that info, you might as well go ahead and implement ATO. |
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| (1135056) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Stephen Bauman on Thu Jan 26 14:46:07 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Thu Jan 26 13:33:22 2012. Then how can it communicate where the block has moved to?There were two moving block systems in operation in NYC more than a century ago. Both were on the Brooklyn Bridge at different times. After 1908, fixed length blocks of 100 feet each were built. In order for a train to enter a block, both that block and the 6 blocks in front of it had to be clear. This enforced a minimum separation of 700 feet which was a restriction of the loading that the bridge could carry. This system enabled the bridge tracks to operate at 66 tph. Speed on the bridge was limited to 16 mph or 24 tph. This means that block moved every 4 seconds. The CBTC system has to allow for sporadic RF failures. The timeout is 2 seconds. This compares favourably with the moving block system of more than a century ago. The predecessor cable provided even better performance. It kept trains a fixed distance between one another regardless of their position on the bridge. The precision and accuracy of that train control system has not been equalled by newer technologies. It even provided rudimentary ATO. All without electricity. As a fixed block system has smaller and smaller blocks, the cost starts going up. NYCT, with its need to have trains running every 2-5 minutes on most lines, has a pretty robust signal system. Being able to get rid of such a "dense" system of fixed blocks should help the MTA reduce costs as the existing signals reach the end of their life cycles. You left out one important detail. Block length is determined by both desired headway (which you mentioned) and also by the expected distance between trains where the block is. When trains are operating at 30 mph at 40 tph, the expected distance between trains is approximately 4000 feet. Short block lengths are not required where trains are already separated by that much. Trains close in on their leader as they approach the station where the leader has stopped. Station approaches and platforms are where shorter block lengths are required for higher service level capacities. Block system designers have the luxury of placing shorter length blocks only where they will be needed. They can use longer length blocks where they are not needed. This allows them to design a system that minimizes the number of blocks (and cost) without compromising service level capacity. |
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| (1135070) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 16:46:04 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Thu Jan 26 13:33:22 2012. Then how can it communicate where the block has moved to?It needs communication. But that doesn't mean the return communication has to control the train. Communication based moving block systems for manual-driving-only exist. Otherwise, there's not much of a point in implementing CBTC. I guess eventually. But you have to remember that most currently in-service CBTC systems are fixed block based yet some of them run on 90-95 seconds headways. And in case of Paris, they've been doing it for over 40 years. What's the point of implementing moving blocks if it doesn't work any better than a 40 year old technology. |
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| (1135074) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Thu Jan 26 16:58:39 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Thu Jan 26 13:35:54 2012. It means that the trains are using wireless communication to let the rest of the system know where they are, how fast they're going, and also receive input on what speed they're allowed to travel at.That is not the definition of CBTC, unless in the US, it means that. And if by wireless, you mean RF based, the CBTC used in Paris and other places are induction loop based but they are definitely Communication Based Train Control. |
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| (1135096) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Thu Jan 26 18:03:30 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Stephen Bauman on Thu Jan 26 14:46:07 2012. There were two moving block systems in operation in NYC more than a century ago. Both were on the Brooklyn Bridge at different times.After 1908,fixed length blocks of 100 feet each were built. So in the first paragraph, you say that it was a fixed block system! I understand what you're getting at, but at the end of the day, even though it was an extremely robust fixed block system, it was just that: fixed blocks. Additionally, examining this system shows why CBTC becomes appealing: you can get signal protection as robust as the system you described for a fraction of the cost. But more on that later. The predecessor cable provided even better performance. It kept trains a fixed distance between one another regardless of their position on the bridge. The precision and accuracy of that train control system has not been equalled by newer technologies. It even provided rudimentary ATO. All without electricity. Pardon my ignorance, but what system is this you're speaking of? A cable car? You left out one important detail. Block length is determined by both desired headway (which you mentioned) and also by the expected distance between trains where the block is. When trains are operating at 30 mph at 40 tph,the expected distance between trains is approximately 4000 feet... Block system designers have the luxury of placing shorter length blocks only where they will be needed. They can use longer length blocks where they are not needed. That's the exact issue that makes CBTC attractive. You don't need to increase the amount of equipment to facilitate shorter blocks as you get closer to the areas where you will need shorter blocks. The benefit is even greater on some commuter or freight roads where the existing signalling might only allow for a much lower frequency, and transponders don't have to be placed so frequently. I honestly don't know how far CBTC technology is, or can be pushed, but you could really save a lot of money if you can get away with limiting the number of transponders on above surface RRs. |
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| (1135149) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Thu Jan 26 23:06:17 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Wado MP73 on Thu Jan 26 16:58:39 2012. That is not the definition of CBTCWikipedia quotes the IEEE's definition of CBTC as a “continuous, automatic train control system utilizing high-resolution train location determination, independent of track circuits; continuous, high-capacity, bidirectional train-to-wayside data communications; and trainborne and wayside processors capable of implementing Automatic Train Protection (ATP) functions, as well as optional Automatic Train Operation (ATO) and Automatic Train Supervision (ATS) functions.” CBTC essentially means that the train is communicating with the network, the network reads that, and then sends the appropriate governance to the train. As the quote above states, CBTC does not mean that the trains will be ATO. In fact, NYCT originally looked at operating CBTC with the R42s, originally operated Canarsie manually, and may outfit R68s with non-ATO capable CBTC equipment in the future. ATO and CBTC are two different things. If the system is still getting the information it uses to govern train movements from track circuits (fixed blocks), then it's not CBTC. You can have ATO without CBTC, and you can have CBTC without ATO. the CBTC used in Paris and other places are induction loop based but they are definitely Communication Based Train Control. True, CBTC can be used with systems other than RF transmission. But the train has to be communicating its speed and location to the system through the same medium it is receiving its governing indications. |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Stephen Bauman on Fri Jan 27 16:28:55 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Thu Jan 26 18:03:30 2012. So in the first paragraph, you say that it was a fixed block system! I understand what you're getting at, but at the end of the day, even though it was an extremely robust fixed block system, it was just that: fixed blocks.No, it's a moving block system. A fixed block system to guarantee 700 foot spacing between trains would have had 700 foot blocks across the bridge. The rule is that two red signals separate the leader from its follower. This means one block behind the leader would also have a red aspect. The distance between the leader and follower could vary between 700 and 1400 feet. The distance between leader and follower for the Brooklyn Bridge's moving block system was between 700 and 800 feet. That gap moved behind the the leader as he crossed the bridge. How does a train know its position in a CBTC based system? There are wayside beacons placed along the tracks. The carborne equipment reads the beacon as it passes it. The beacon may be an RF transponder, an RFID tag, an optical barcode or some other technology. It's supposed to be a lot cheaper install and maintain than an insulated joint. It was the failure to read these beacons that caused some of the early delays on the 14th Street Line installation. The system did not loose trains; the trains themselves did not know where they were. The internal control software does not measure train position in feet, meters, miles or microns. It measures them in integer block lengths as determined by the positioning of the beacons. The spacing of the beacons is determined by the desired maximum service level. Spacings between beacons of 100 to 600 feet is usual. While such spacings are adequate for collision avoidance, they are not for ATO where trains have to stop to a much tighter tolerance. Dead reckoning by counting wheel revolutions is used in addition to the beacons to make ATO stop near the same mark. You will note that the spacing between beacons is about the same as the spacing between insulated joints. Moreover, the algorithm used by the CBTC's "moving block" system are exactly the same as was used on the Brooklyn Bridge more than a century ago. The only possible difference besides implementation is one of scaling. Pardon my ignorance, but what system is this you're speaking of? A cable car? Don't knock the New York And Brooklyn Bridge Railway. The cars were 10 feet wide. The trains were longer than those on the El's on the Brooklyn and Manhattan sides. They also averaged 90 second headways over a continuous 24 hours with 80+ tph peak service after 1893. The cable was not only a partial ATO propulsion system but also ultimate moving block system for traffic control. As we used to say when I worked on the Apollo program, "if it works it's not sophisticated." You don't need to increase the amount of equipment to facilitate shorter blocks as you get closer to the areas where you will need shorter blocks. The CBTC equipment must be capable of handling maximum demand at all locations. Whether this is cost effective depends on the percentage of track is in or near stations and the CBTC equipment cost. An installation like the 14th Street Line should have favoured CBTC costwise because its large number of stations and short route length. That has not been the case. The benefit is even greater on some commuter or freight roads where the existing signalling might only allow for a much lower frequency, and transponders don't have to be placed so frequently. The way to handle long distance freight lines is to use GPS for determining the train's position. |
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| (1135267) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Fri Jan 27 17:05:51 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Thu Jan 26 23:06:17 2012. independent of track circuitsThat part is new to me. Oh well. |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Fri Jan 27 17:56:08 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Wado MP73 on Fri Jan 27 17:05:51 2012. Curious: what does Paris' line 14 use? |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Fri Jan 27 19:01:09 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Stephen Bauman on Fri Jan 27 16:28:55 2012. No, it's a moving block system. A fixed block system to guarantee 700 foot spacing between trains would have had 700 foot blocks across the bridge.No, it's a fixed block system. It doesn't matter if there were 20 blocks behind the train. Each signal block is in a fixed location. That location doesn't move. The amount of signals set to DANGER behind defined an area that trains could not enter. As a train vacated a block 6 blocks away, the first one would clear. The advantage here is that unlike the 700' long block you mentioned, where the tail of that train could be anywhere within that 700', we can now pinpoint that train to a 100' distance. Whatever the CBTC system used, the blocks are not fixed in nature. Even if it's using integer block lengths, and those blocks are defined by the locations of the beacons, the area that a train cannot enter is not fixed. Where as a signal aspect will always be encountered at 135+50, along some line, on a CBTC line, the point a train cannot enter moves, based upon the location of the train. There are no fixed locations that will stop a train. A preceding train is allowed to get to a certain distance from its leader, based upon a certain allowance for the system's deficiencies. CBTC is also more sophisticated than fixed blocks, because it allows trains to have their speed governed based on distance to the leader, which fixed block systems can only do but so well (and that adds cost to the fixed block installations). Don't knock the New York And Brooklyn Bridge Railway. The cars were 10 feet wide. The trains were longer than those on the El's on the Brooklyn and Manhattan sides. They also averaged 90 second headways over a continuous 24 hours with 80+ tph peak service after 1893. The cable was not only a partial ATO propulsion system but also ultimate moving block system for traffic control. As we used to say when I worked on the Apollo program, "if it works it's not sophisticated." Not knocking it, but how does such a system provide signal protection for stopped trains that have released the cable? The CBTC equipment must be capable of handling maximum demand at all locations. Whether this is cost effective depends on the percentage of track is in or near stations and the CBTC equipment cost. An installation like the 14th Street Line should have favoured CBTC costwise because its large number of stations and short route length. That has not been the case. Has more to do with the chosen implementation than the system. The way to handle long distance freight lines is to use GPS for determining the train's position. Yes, I agree! And what if PTC were implemented through those same GPS satellites? It would be a train system with no fixed blocks, and where train control was through a wireless communications system... |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Fri Jan 27 22:23:19 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Fri Jan 27 17:56:08 2012. Line 14 is induction loop based CBTC.The automation of line 1 is the first RF based CBTC in Paris. Right now, older MP89 with induction loop based ATO with driver co-exist with RF based ATO MP05 with no driver. The MP89 will soon be gone from line 1. Both ZPTO systems were developed by... aarrrgh, Siemens! |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by J trainloco on Fri Jan 27 22:40:23 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Wado MP73 on Fri Jan 27 22:23:19 2012. About the induction loop CBTC: how does it detect trains? I get that it uses induction loop to communicate to the trains, but is it also using induction loop to determine train position?Siemens... I know. Are they moving to automate the rest of the system? With Siemens? |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Fri Jan 27 23:30:47 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Fri Jan 27 22:40:23 2012. The induction loop on line 14 can be used for both one-way ground-to-train and two-way communication. I believe it uses different frequencies for send and receive data. When an older stock runs on the line, it uses traditional fixed blocks. The MP89CA will use what they call "virtual blocks", which are much shorter software based blocks rather than physical track circuit blocks. They are still not moving blocks though. If an MP89CA loses contact with the PCC (Command Center), it will be treated as older stock and falls back to one-way communication and traditional fixed blocks.As for automation of other lines, the logical move is to automate line 4 or 13 next but I think it's still up in the air. It's up to the success of line 1. The relay at line 13's southern terminus is already automated. Trains leave the arriving platform, relay and come back to the departing platform by themselves. I still can't get over how Siemens used the L as a guinea pig and left NYCT with a proprietary, semi-finished product so they can sell a finished product to RATP. |
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Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Outside the Box on Sat Jan 28 14:09:57 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by J trainloco on Fri Jan 27 22:40:23 2012. The Flushing Line CBTC will be with Thales SelTrac. The firm is multinational, but the technology was originally German for a Maglev. Its been adapted in various forms to dozens rail of systems over the past 3 decades. |
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| (1135550) | |
Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ... |
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Posted by Wado MP73 on Sat Jan 28 20:30:32 2012, in response to Re: Latest updates: R-179 order saga, R-160 CBTC for (L) line & special reports ..., posted by Outside the Box on Sat Jan 28 14:09:57 2012. Same as London's DLR and JFK Airtrain. I guess it's a good thing. |
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