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| Re: TA is obsessed with CBTC, and ''New'' tech for no reason. (578118) | |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Forest Glen on Fri Feb 29 23:34:59 2008, in response to TA is obsessed with CBTC, and "New" tech for no reason., posted by JournalSquare-K-Car on Thu Feb 28 22:08:34 2008. CBTC/ATO has worked on transit systems in Washington DC and San Francisco. It can work in New York. This is the 21st century. New Yorkers deserve a modern and reliable system. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by G1Ravage on Fri Feb 29 23:36:24 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by North-Easten T/O on Fri Feb 29 12:59:24 2008. Ah...so that's that moveable blocks are. I was wondering why the signals only flashed green between Canarsie - Rockaway Parkway and Broadway Junction, and between Third Avenue and Eighth Avenue. There's also a flashing signal northbound entering Myrtle - Wyckoff Avenues, all by itself.I sometimes look at the ATS screens in the dispatcher's office, and see the "blocks" that sort of move along with the train. Unless the train is yellow. ;-) |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Railman718 on Fri Feb 29 23:38:41 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Forest Glen on Fri Feb 29 23:34:59 2008. CBTC/ATO has worked on transit systems in Washington DC and San Francisco. It can work in New York. This is the 21st century. New Yorkers deserve a modern and reliable system.You are forgetting ONE important thing. Those systems was built right with CBTC/ATO. This 100 year old system was never built for that. So you are taking 100 year old stuff and trying to use 21 century technology with it what do you think is going to happen? Does the term square pegs and round holes mean something? |
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| (578686) | |
Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Pelham Bay Dave on Fri Feb 29 23:41:43 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Fri Feb 29 21:11:28 2008. Right now its a pain in the neck. I agree when it becomes 100% and they change some things like you speed being reduced to 3MPH 2 or 3 car lenghts from a red signal. They also need to reduce the work zones in the area where the work is being performed. I hate it every night I got to do 8 MPH in the River tube because I got "Work Zone in Progress" from Bedford Ave to North of 1 AV which result in a 15 Minute late clear and my operating hand in pain from the controller. I have seen the good side of it. On the other hand if your following a train in Bypass you really have to look at your MAL. I spend more time looking at the computer to make sure my speed and conditions are in the green more then I get to look at the roadbed which is another complaint I got. Everytime I take my eyes off the computer its starts beeping then that gets me nerves thinking I am one step from a BIE and I just go into a full service brake until the alarm goes off. Hopefully its just the lack of CBTC experance factor which I hope to master before this pick ends. I can tell you this I won't be back on the L Line next pick. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Stephen Bauman on Fri Feb 29 23:44:41 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Forest Glen on Fri Feb 29 23:34:59 2008. CBTC/ATOCBTC and ATO are two different items. One can build an ATO system without CBTC. Washington and San Francisco (BART) have done it. The MUNI is CBTC - using inductive loop. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Forest Glen on Fri Feb 29 23:47:15 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Fri Feb 29 23:38:41 2008. The London Underground is even older than the subway. However, they built the high tech Jubilee line. |
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| (578694) | |
Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Train Dude on Fri Feb 29 23:47:50 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by JournalSquare-K-Car on Fri Feb 29 21:56:03 2008. It's written in the Jibber dialect. You should be able to find a good Jibber-English translation software on line. |
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| (578696) | |
Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by trainsarefun on Fri Feb 29 23:56:10 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Forest Glen on Fri Feb 29 23:34:59 2008. CBTC/ATO has worked on transit systems in Washington DCWMATA uses CBTC? WMATA's ATO seems to be the cause of a lot of their delays, actually, and platform overshoots, which seem to be concentrated in bunches (which is strange, because given the pattern, one might think that they'd revert to control by the train engineers at the first sign of trouble, but historically at least, WMATA seemed quite biased against doing that). It can work in New York. This is the 21st century. New Yorkers deserve a modern and reliable system. Is the traditional block system used by NYCT not reliable? (If you're tempted to answer 'no', then think of incidents in which WMATA accidents have led to NTSB reports in the last two decades or so, and the potential loss of life and risk of injury). That said, some aspects of CBTC will be a positive - positive train control and all of that - as applied to NYCT, let's see. We'll also see how PATH does with it, in our area. I assume that LIRR has chosen firmly not to experiment with CBTC (from 6/1999 Railway Age): On the Long Island Rail Road, there are nearly 300 grade crossings, which present a formidable safety problem. New Hyde Park, where one of the busiest crossings is located, is the site of the Intelligent Grade Crossing demonstration, which is being conducted with the New York State Department of Transportation and FRA. With technology provided by Alstom Signaling, LIRR is attempting to demonstrate the basic capability of CBTC to deliver consistent grade crossing warning times, and its ability to be integrated with ITS. Alstom Signaling is currently re-engineering the test installation to be compatible with the SACEM-based CBTC technology it's testing for the Canarsie Line project. LIRR's grade crossing program is a key part of its 20-year, $700 million Signal Strategy program, inaugurated two years ago. LIRR plans to adapt whatever CBTC system sister agency New York City Transit selects. Its long-term objective is to implement CBTC system-wide-what President Tom Prendergast calls an "all or nothing" approach. LIRR, like most commuter rail agencies, is finding it increasingly difficult to keep up with growing ridership. New signaling technology, Prendergast feels, is not developing fast enough to keep up with demand. "My fear is that we will have to remain committed to a signal system with limited throughput and safety capacity," he says. Compare to the 9/2007 LIRR Assessment. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by trainsarefun on Fri Feb 29 23:58:39 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Fri Feb 29 23:38:41 2008. Does the term square pegs and round holes mean something?Not only that, but it seems that Siemens has chosen to opt a different way for NYCT's CBTC system. You can cross your fingers, but so far at least there's a lot to be pessimistic about. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Jeff H. on Sat Mar 1 00:08:11 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by trainsarefun on Fri Feb 29 22:43:03 2008. Suppose further that with CBTC, trains are allowed toapproach the wall at 8th Av up to (and in fact at) the speed limit that would enable an emergency stop short of the wall. That would be called suicide. There is a margin of safety built in to the movement authority limit, of course. Any system which relies on fixed trips is what is called an "intermittent train control" system. The design margins must be higher because the designer only has the ability to control the train by tripping it at certain points. This makes things like speed control very awkward. Traditional cab signal systems with ASC are continuous train control, as is CBTC. The primary theoretical advantage of a communications based approach is that the train has the ability to talk back to the wayside system and indicate its ability to stop. This must be integrated with the propulsion and braking controls in a vital (life-safety critical) manner, which makes it a difficult and expensive design. I believe this "stop-assure" is of dubious value since the NYCTA went with their traditional friction brakes only during emergency approach, and thus there isn't too much variability in stopping distance due to car equipment factors (roadbed conditions are another story). In the NYCT implementation of CBTC, interlockings are done almost like traditional relay-based interlockings, with fixed home signals and trips. There was never any claim of improved interlocking performance, other than the automatics approaching the plant. As Baumann has repeatedly explained and calculated, terminal capacity in a 2-track stub is all about how quickly you can get a train to clear the crossover and normal up the switch. Incidentally, part of the long-term signal strategy is to get rid of pneumatic switches. If switch operating time is an important concern, those air switches have a few second advantage over their electric counterparts. Traditionally, timers were designed to "prove" that the train is under control and operating below a certain speed. It was assumed that, e.g. when approaching a bumping block, the motorman would not decide to commit suicide and wrap up the ccontroller the instant that the last stop arm goes down. The new signal design guidelines pretty much make that assumption, to the point that they are attempting to apply continuous train control principles to an intermittent system. That makes the cost of doing any new signal work so high that CBTC starts to look good. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Jeff H. on Sat Mar 1 00:09:03 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by South Brooklyn Railway on Fri Feb 29 21:36:20 2008. I didn't know you spoke Russian. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by trainsarefun on Sat Mar 1 00:20:53 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Jeff H. on Sat Mar 1 00:08:11 2008. OK, that firms up a lot of things. Essentially, at least on the Canarsie Line, what's being gained by CBTC are the continuous safeguards afforded by PTC above and beyond those given by the traditional intermittent signal system, but since the lowest capacity item on a line limits capacity, even if the CBTC system could handle a service frequency of 30 tph, the fact that 8th Av - and Canarsie isn't a quicker terminal from what I've read here, though I haven't actually seen that it action - can only handle 24 tph renders what the CBTC system can do really quite moot in terms of service.Overall, CBTC is basically buying - on the Canarsie Line - the safety advantages of PTC - is that fair to say? |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by JournalSquare-K-Car on Sat Mar 1 00:32:07 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Jeff H. on Sat Mar 1 00:08:11 2008. WOW. They really think motormen are maniacs. even if you wrap it around after the last arm goes down, you will only be able to hit 15, maybe 20 miles-not enough to commit suicide with a bumper. You might even be able to tow the train away. the most that can happen is a delay for a day, and lawsuites due to "injuries".PATH is far more reasonable in this sense. Hah, and that replacement of AIR with Electric switches seems dumb-dumb too. They use air for the sump pumps anyways, and if it ain't broke, don't BREAK it. They can't fathom that an old system CAN be reliable, as it was for a century. Why reinvent the wheel? I can imagine the elctric switches getting jammed, and then the tremendous currents overheating the components. Air doors were superior in this sense as well. Also electronics don't like the damp environment where manny switches are located. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by JournalSquare-K-Car on Sat Mar 1 00:37:54 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Pelham Bay Dave on Fri Feb 29 23:41:43 2008. Another thing: the new controllers are not ergonomic from what i hear. A real controller like on the 32's seems more comfortable, and natural. You can also use both hands to hold it down. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by JournalSquare-K-Car on Sat Mar 1 00:39:18 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Jeff H. on Sat Mar 1 00:09:03 2008. I don't get it though. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 00:40:11 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by JournalSquare-K-Car on Sat Mar 1 00:32:07 2008. Ummm ... no ... you can do some mighty *serious* damage at only 3 MPH. Trust me ...
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by R30A on Sat Mar 1 00:41:42 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by SelkirkTMO on Sat Mar 1 00:40:11 2008. That your train? |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 00:56:23 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by R30A on Sat Mar 1 00:41:42 2008. I *believe* so ... been told it was and sent to that photo, but don't remember the car number after all these years so have to go with what I was told. Didn't realize it was THAT extreme at the time. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by R30A on Sat Mar 1 01:11:16 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by SelkirkTMO on Sat Mar 1 00:56:23 2008. That shattered glass musta been bad. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Jeff H. on Sat Mar 1 01:16:02 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by trainsarefun on Sat Mar 1 00:20:53 2008. I would cautiously say that CBTC is a safer system thanwaysides signals and trip, on the average. BUT, whenever you dumb it down there is a long-term risk that the operating personnel will sink to the level you set for them. When that happens, you have a degraded ability to respond in the field to unusual situations. Most accidents with PTC systems are not because of "false-clear" signal failures, but secondary things which happen during failure work-around, or out of the ordinary moves. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 01:28:06 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by R30A on Sat Mar 1 01:11:16 2008. That's the weird part of the photo ... yes, the top did crack, but it didn't break as best I remember (was a bit dazed after the event) and while I'm told that was *my* wreck by a former motorman who pointed it out to me, didn't seem so severe at the time. But they said it's mine ... OK. All I remember is hitting the train ahead of me, mine went sideways to the right and I guess it must have caught the roof of the arnine ahead of me when the truck went off the track sideways. I just remember looking at the anticlimber curled up, but that's all I remember. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by R30A on Sat Mar 1 01:29:55 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by SelkirkTMO on Sat Mar 1 01:28:06 2008. Could that have been the one that was hit then?Both were R1-9s, right? |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 01:33:10 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by R30A on Sat Mar 1 01:29:55 2008. Possible. FWIW though, I was told that was the car I was operating ... and yes, when I lost my brakes, right into a parked F train of arnines after the call-on. :( |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Grand concourse on Sat Mar 1 04:39:25 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Forest Glen on Fri Feb 29 23:34:59 2008. What is your obsession about "a modern and reliable system"?1st of all the system isn't getting the funds it needs to clean up and fix up every single station to the same levels as your favorite DC or PATH systems. Also do those systems run 24/7? If they did then there would be no way they could clean those stations as well as keep ppl out for at least 6 hours. If NYC closed down for 6 hrs sure lots of stations can be cleaned up and energy would be saved by not having to run any trains, but being NYC no major lines can stay shut down, not even for an hour. So if you hate the NYC subways so much then take the express buses that you love so much or move to Jersey so you can ride the PATH everyday. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by trainsarefun on Sat Mar 1 07:13:08 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by SelkirkTMO on Sat Mar 1 00:56:23 2008. Do you recall what the trained was signed up as in the front; seems unlikely that with that kind of damage the sign would be changed after collision. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Stephen Bauman on Sat Mar 1 07:34:42 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by JournalSquare-K-Car on Sat Mar 1 00:32:07 2008. you will only be able to hit 15, maybe 20 miles-not enough to commit suicide with a bumper.The train in the Williamsburg Bridge wreck was estimated to be traveling at 18 mph. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 07:40:45 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by trainsarefun on Sat Mar 1 07:13:08 2008. I had a (D) ... train ahead of me was an (F) ... "be governed accordingly." I guess after the wreck, "No PAX." :) |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 07:42:46 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Sat Mar 1 07:34:42 2008. That's some velocity. No wonder it telescoped. As I demonstrated separately, you can do some SERIOUS damage at only 3MPH with all the momentum in a rolling train. :(Wonder how fast the "terminal velocity" of that [M] train was at Chambers? Betcha from the damage, it was around 3 or so as well ... |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Railman718 on Sat Mar 1 08:01:22 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Forest Glen on Fri Feb 29 23:47:15 2008. The London Underground is even older than the subway. However, they built the high tech Jubilee line.We arent talking about London here. We are talking about New York. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by South Brooklyn Railway on Sat Mar 1 08:05:30 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Train Dude on Fri Feb 29 21:50:55 2008. Exactly. Thats one job you do NOT want to fool around in. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 08:06:34 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Sat Mar 1 08:01:22 2008. Dayum ... I woulda thought you'd come up with "Jubilee" is a BRAND NEW LINE! Built from scratch! Of COURSE they can do whiz-bang! Bro ... yer slipping! :) |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by SelkirkTMO on Sat Mar 1 08:11:33 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by South Brooklyn Railway on Sat Mar 1 08:05:30 2008. "You speaka Russkie" was really the point ... lemme put it to you THIS way ... RUSSKIE techs are *damned* serious science, and they KNOW their chit ... but looks like signal dept is full of Russkies ... you pull YOUR weight, you RESPECT, and you get along and those guys are WONDERFUL to work with ... ME got Russkies working with me, and couldn't be happier! Dude mentioned that in another thread reply ...SERIOUSLY though ... you'd better have SUPER human hearing for those ceramics clanking from an approaching train, AND ... heed his advice ... track safety is no joke. KNOW where your bailout is wherever you are out of "railroad" and my hat's off to you ... being potential "train meat" is a serious undertaking ... KNOW the rulebook, and don't *EVER* let someone tell you to do something contrary to the book ... EVER! Hat's OFF to you for going out for that ... figgered you'd do monkey suit and then wait to move up front ... you're off into a DANGEROUS task there, kiddo. :( |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by South Brooklyn Railway on Sat Mar 1 08:45:01 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by SelkirkTMO on Sat Mar 1 08:11:33 2008. Heh, well hey, I got to make my money. And come on, it's my foot in the door with TA. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 08:47:18 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Fri Feb 29 21:11:04 2008. Obviously, the TA has to finish the job (no, really?) If I only replace the corroded pipes in ,y house but not the corroded city intake then I can't benefit yet... |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 08:49:46 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by South Brooklyn Railway on Sat Mar 1 08:45:01 2008. Good luck to you. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Railman718 on Sat Mar 1 08:52:54 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by SelkirkTMO on Sat Mar 1 08:06:34 2008. Dayum ... I woulda thought you'd come up with "Jubilee" is a BRAND NEW LINE! Built from scratch! Of COURSE they can do whiz-bang! Bro ... yer slipping! :)I knew that just didnt feel like adding it in my post.. What London does has nothing to do with New York. ;o) |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Railman718 on Sat Mar 1 08:58:27 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by JournalSquare-K-Car on Sat Mar 1 00:37:54 2008. Another thing: the new controllers are not ergonomic from what i hear. A real controller like on the 32's seems more comfortable, and natural. You can also use both hands to hold it down.They tried to tell them that that controller on the R143's and R160's wasn't right but typical MTA(back then) didnt listen anyway.. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Railman718 on Sat Mar 1 09:01:19 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by RonInBayside on Sat Mar 1 08:47:18 2008. Obviously, the TA has to finish the job (no, really?)YES really.. A "job" that was started sometime in the late 90's yeah.. I will send you a email when they are done. If I only replace the corroded pipes in ,y house but not the corroded city intake then I can't benefit yet... Then i suggest you stop killing idle time here and get it done then.. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:15:19 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Sat Mar 1 09:01:19 2008. It took two weeks to get everything done on my house's plumbing. I have a 103 year old house. I got rid of all the galvanized steel pipe and replaced it with copper pipe. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Stephen Bauman on Sat Mar 1 09:16:28 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Jeff H. on Sat Mar 1 00:08:11 2008. Any system which relies on fixed trips is what is called an "intermittent train control" system...Traditional cab signal systems with ASC are continuous train control, as is CBTC.That's a bit misleading because all are sampled data (discrete) systems. The position data is discrete, in that the data is the same regardless of where a train is within a block. The data can change only when the train crosses an insulated joint. Similarly, the instructions for a follower can change only when the follower is about to cross an insulated joint. So, where's the safety benefit for cab signals? The instructions will change the instant the follower crosses an insulated joint. This is usually where signals and trippers are placed for an all wayside system. Any benefit would be in allowing the follower to speed up more quickly, should the leader put more distance between them. Even here the benefit for a "continuous" cab signal is an illusion. T/O's are permitted to peek out the window and look at the aspect of the signal ahead of them. CBTC data is also discrete, even with a continuous block system. The sampling is in time, not distance. The control system knows the status of the leader and follower. However, these statuses were taken at different times. The control system must take into account the non-simultaneity of the data. One can equate the margins required for these time differences to those for a block system. Not surprisingly, CBTC is equivalent to a fixed block system with 100 to 150 foot block lengths. The average distance between signals on NYCT is 350 feet. The usefulness of such a small block length is questionable, considering how infrequently the distance between leader and follower needs to be within this range. Traditionally, timers were designed to "prove" that the train is under control and operating below a certain speed. It was assumed that, e.g. when approaching a bumping block, the motorman would not decide to commit suicide and wrap up the ccontroller the instant that the last stop arm goes down. The new signal design guidelines pretty much make that assumption, to the point that they are attempting to apply continuous train control principles to an intermittent system. Perhaps, the signal engineers should defer to the EE's who have contended with sampled data systems since the 1920's. The question of the suicidal T/O can be solved by using the Nyquist Sampling Theorem. Acceleration is analogous to maximum frequency. That determines the number of timers and their positions before the final tripper before the block. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:22:33 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Sat Mar 1 09:16:28 2008. "So, where's the safety benefit for cab signals?"Wayside signals can be obscured by snow, ice, mud; each wayside signal can fail, resulting in an absolute stop. A cab signal can fail too, but it is inside the cab, out of the weather. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Wado MP73 on Sat Mar 1 09:22:38 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Fri Feb 29 22:46:20 2008. Good read. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:28:11 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Fri Feb 29 22:46:20 2008. Nothing in the article you cite says that a component "cannot be manufactured." As usual, you misinterpret what you read. You come up with an opinion first, then selectively interpret according to it.You'd make a good Bush appointee. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:28:44 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Wado MP73 on Sat Mar 1 09:22:38 2008. But not supportive of Stephen's opinion. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Stephen Bauman on Sat Mar 1 09:29:08 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Jeff H. on Sat Mar 1 01:16:02 2008. I would cautiously say that CBTC is a safer system than waysides signals and trip, on the average.I wouldn't. Avoiding a collision by an mile rates the same safety score as avoiding one by an inch. If CBTC does enjoy any benefit, it's in the area higher service levels for the same degree of safety. However, the existing wayside system with "discrete" trippers permits service levels far in excess of what is currently operated. When service levels begin to approach what the current system permits, then it may be time to examine this question again. The theoretical service level improvement for CBTC will be less than 5% over the current system. This may be sufficient to justify its use under certain circumstances. It isn't just now nor for the foreseeable future of anticipated service levels. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Railman718 on Sat Mar 1 09:29:18 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by RonInBayside on Sat Mar 1 09:15:19 2008. What type of copper piping?K L or M?? |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:31:41 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Fri Feb 29 21:01:37 2008. "It's not a trivial problem because a critical component of the carborne CBTC equipment is no longer manufactured"Also not a long-term issue. While a redesigned component will increase the cost to somec extent, this is far from an insurmountable obstacle. |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:33:32 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Fri Feb 29 23:30:58 2008. "shortest-enduring radios"What does that mean? |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:34:20 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Railman718 on Sat Mar 1 09:29:18 2008. Dunno. Gotta ask my plumber. (I paid a master plumber to do it). |
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by RonInBayside on Sat Mar 1 09:59:30 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Sat Mar 1 09:29:08 2008. "The theoretical service level improvement for CBTC will be less than 5% over the current system."And since you've spent your life designing railroad signalling, you'd know. |
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