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Post by Admin Team on Feb 28, 2005 21:47:08 GMT
I've had a few enquiries about how the GPS link works whilst the train's in covered sections of the line.
I've emailed the project engineer of the company in Denmark that's producing the kit asking the question, so as soon as I get a response I'll share it with you.
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Deleted
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Post by Deleted on Feb 28, 2005 23:21:47 GMT
Wonderful! Although TBH I'd rather they got the Connect project on track  |
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Colin
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My preserved fire engine!
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Post by Colin on Mar 1, 2005 0:56:39 GMT
From what i remember at the drivers briefing i attended, someone asked the same question. The answer given was that if the GPS system lost contact with the satelite, it would revert to the old system of mesuring wheel revolutions, just like it does on the C stock.
That's what we were told anyway.
I can't help thinking it's a waste of time (and money)fitting this sort of technology to trains that spend time underground and will be scraped in few years.
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Deleted
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Post by Deleted on Mar 1, 2005 3:26:46 GMT
From what i remember at the drivers briefing i attended, someone asked the same question. The answer given was that if the GPS system lost contact with the satelite, it would revert to the old system of mesuring wheel revolutions, just like it does on the C stock.. This is what I was told aswell, also when setting up in tunnels you will need to scroll through the station list for your current location, where in open sections the GPS gives you your current location, won't stop us going the wrong way though  |
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Post by Admin Team on Mar 1, 2005 7:54:26 GMT
This is what I was told aswell, also when setting up in tunnels you will need to scroll through the station list for your current location, where in open sections the GPS gives you your current location, won't stop us going the wrong way though I too believe that's the way it works, but as I've the opportunity to get some words from the actual manyfacturers it seems too good an opportunity to miss. And, of course, it has now been 'some months' since we were briefed on it, and the other mods too........ As for 'misdirected moves' - well, we'll just have to try it out, eh Jim? ;D |
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Post by Admin Team on Mar 1, 2005 7:56:08 GMT
Wonderful! Although TBH I'd rather they got the Connect project on track It IS coming - honest! |
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Post by Dmitri on Mar 2, 2005 11:52:32 GMT
Hope you'll keep us informed  . |
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Post by Admin Team on Mar 2, 2005 21:09:07 GMT
I certainly will..... However, the latest is that they're now passing round information about the installation on various stocks - we've had a team give us a brief talk about it (and we got a mug!  ) I'm down to do briefings on it when it's introduction is 'imminent' - so *hopefully* I'll know the dates........ |
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Post by piccadillypilot on Mar 4, 2005 20:32:55 GMT
As for 'misdirected moves' - well, we'll just have to try it out, Look on the bright side, in such a situation the GPS should be able to set the bells ringing in the control room. That'll save the poor unfortunate driver getting an earful when phoning in from North Ealing. |
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Post by Deleted on Mar 5, 2005 2:18:57 GMT
Look on the bright side, in such a situation the GPS should be able to set the bells ringing in the control room. That'll save the poor unfortunate driver getting an earful when phoning in from North Ealing. My understanding of it is that it won't send two way locational information to the Control Room, it's purely there to tell the Customer Information System on the train where it is. So we would still have to make that embarrassing call |
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Post by Admin Team on Mar 5, 2005 10:15:56 GMT
For the benefit of those of you who may be wondering what these last two messages are about.......
You may have read my story 'Confession Time' about taking a wrong route at Hanger Lane Junction in the first half of last year. Jim had done the same thing just a couple of months before!
Suffice it to say that we're reminded of our little 'error' on every possible occasion!
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Deleted
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Post by Deleted on Mar 5, 2005 15:50:43 GMT
What, has someone decided to post a sign in the armpit of the junction saying "DAVE, JIM - TURN LEFT OR RISK MY WRATH - STEVE" ;D ;D |
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Post by James on Mar 9, 2005 20:20:19 GMT
Incidentally, given the imbalance in tph between the two branches of the Picc, is there any chance of the Rayners branch seeing real trains again (other than by accident  )? |
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Post by Admin Team on Mar 9, 2005 20:35:09 GMT
Ah - the Uxbridge branch!
This is an old chestnut that comes up from time to time, for a variety of reasons.
The latest I've heard is that we'll get it back, but whether that means an increased service I don't know - after all it's supposed to be every 10 minutes now, and passenger volumes don't justify more than that, though reliability is I know at present an issue.
I use the branch myself, so I know the frustratioons it brings on occasions.
There's all sorts of issues involved - some technical, some contractural. But (as it seems you use the branch?) I'm sure you know that when the 'Picc' has problems the first thing to be sacrificed is the Rayners service - this is to do with the commitment to run 'x' tph to Heathrow.
T5 at Heathrow will cause increased demands on the 'Picc' I'm sure, so I'm sure that they'd be glad not to have the distraction of the RL service.
But, at least at the moment, the District doesn't have the rolling stock to simply take it over whilst maintaining all the other routes. Of course, that could change with the introduction of the new trains which could be timed to (more or less) coincide with the opening of T5.
If you want a personal opinion (and it's no more than that!) I have a feeling that one day it will return to the District.
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solidbond
Staff Emeritus
'Give me 118 reasons for an Audible Warning on a C Stock'
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Post by solidbond on Mar 9, 2005 21:35:16 GMT
Ah - the Uxbridge branch! I use the branch myself, so I know the frustratioons it brings on occasions. Intentionally or accidentally? ;D ;D |
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Post by Deleted on Mar 9, 2005 21:52:35 GMT
Intentionally or accidentally? ;D ;D BURN! ;D |
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Post by q8 on Apr 12, 2005 17:05:25 GMT
I think Dave is right that the DR will one day get the Uxbridge branch back but sooner rather than later. If the District stopped going to the Broadway and ran an Uxbridge Tower Hill service and Richmond/Upminster with Wimbledon/ Barking/Dagenham East I think there will be enough stock to cover. We used to do Ealing/Mansion Houses off peak with a 7+half minute headway and once past Embankement you were virtually empty anyway so I don't think there would be a lot of call for "whole line" service in the slack. P.S Do they still have half spare/half runner turns and one rounders like we did?
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Deleted
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Post by Deleted on Apr 13, 2005 1:44:19 GMT
P.S Do they still have half spare/half runner turns and one rounders like we did? Yeah, still a few half spare/half running turns about! I prefer to do the work on the first half with the spare (or DMI - Duty Managers Instructions as they call it these days) bit on the back half, then hopefully you get an early finish! Not that it happens very often! |
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Post by Deleted on Apr 13, 2005 9:38:11 GMT
Suffice it to say that we're reminded of our little 'error' on every possible occasion! This new GPS system will have its benefits as when the train gets to North Ealing it will announce: This is North Ealing, This is your District Line to South Harrow! |
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Post by q8 on Apr 13, 2005 14:37:47 GMT
 Tell me, this system of measuring wheel rev's on "C" stock. Is it done from the motored wheels or trailer wheels? What happens if you get wheel lock/spin? I suppose the system then puts miles on the record.
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Colin
Advisor
My preserved fire engine!
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Post by Colin on Apr 13, 2005 19:29:26 GMT
Tell me, this system of measuring wheel rev's on "C" stock. Is it done from the motored wheels or trailer wheels? What happens if you get wheel lock/spin? I suppose the system then puts miles on the record. Over to solidbond on this one!! |
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solidbond
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'Give me 118 reasons for an Audible Warning on a C Stock'
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Post by solidbond on Apr 13, 2005 20:45:45 GMT
Over to solidbond on this one!! Thanks for that Colin I believe that it is taken from the wheels on the motor car, however there is an allowance built in to allow for slight changes in the wheel profile, wheel slip/slide, and slight variations in stopping position (;D) Once the doors have opened, and it is happy that it is in the correct position, then the counter is reset for the next station. Thus, as an example, if it is determined that the normal distance between point A and point B is 650 wheel revolutions, it will be happy that anything between 640 - 660 wheel revolutions is correct, bearing in mind that it is activated when the door open buttons are pressed. Working on the basis that a Train Operator will only open the doors at a station, it seems to work quite well. There are however, a few places where you get a position error come up. In particular, Southfields W/B and Earl's Court pfm 1 coming from Olympia. This could be that, given the example above, they calculated that it would be 650 revolutions, but it is actually 656. Thus, a train with wheels ground down to the minimum, may actually take 661 revolutions. In this case the position error warning will come up, and the Train Operator can confirm that the position is correct, or re-programme the whole thing from the beginning, (or more likely switch it off ) I will stress that this is just my understanding of the system, and may not be totally accurate, and anyone who knows different is welcome to correct the information (just make sure you don't have me for your next C stock refresher if you do (  ;D ;D) |
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Post by q8 on Apr 14, 2005 0:44:38 GMT
Thanks Solidbond for the explanation. Seems to me all the more reason for a laser type speedometer or something similar to that fitted to aircraft at one time which was a little fan driven by air prssure from the forward motion.
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Post by igelkotten on Apr 14, 2005 23:57:46 GMT
Thanks Solidbond for the explanation. Seems to me all the more reason for a laser type speedometer or something similar to that fitted to aircraft at one time which was a little fan driven by air prssure from the forward motion. Then again, having seen what light, powdery snow can do to the laser sensors of a tamping machine, I am not so sure a laser-based speedo would be much better. Anyhow, regarding measurign of speed: As I said in an earlier post, an inherent characteristic of modern semiconductor-based traction control systems is that they measure the speed of the powered axles, since they work by giving the traction motors pulses of traction current. This can lead to some intersting situations, such as the one I had tonight. I was driving a train with unit 2001 as the southermost car. This train had a very annoying tendency to jerk on braking, especially when I was in the final phase of stopping at a station and fanning off the brake to come to a smooth standstill -which was followed by a back-and-forth jerk of the car. At first, i thought the culprit was 2001, which is the first C20 delivered, and one that we almost tested to death during trials and acceptance running. It's carbody is literally deformed after a series of tests with maximum overload. I had notified Line Control, and they had in turn contacted the depot, and a train technician was going to be sent out to have a look at the train. As it turned out, once I started wading through the fault logs, the A/MA main traction converter in my second car, had reported an enormous amount of intermittent wheel diameter faults. That is, the measured wheel diameter did not match with the wheel diameter entered into the traction control system, which in turn meant that the two southernmost bogies on that car were sort of half out of step on traction and braking with the rest of the train, something that was, as the fitter determined, excacerbated by the rather poor state of a coupler. Anyhow, it was determined that the fault was more of a comfort nature, at least short-term, and that I would continue in service with the train all the way into the depot a few hours later. The train technician did ask me to refrain from ripping the train in two, however, which led to some interesting looks from the dear passengers. ;D /Igelkotten |
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Tell me, this system of measuring wheel rev's on "C" stock. Is it done from the motored wheels or trailer wheels? What happens if you get wheel lock/spin? I suppose the system then puts miles on the record. 
;D ;D)
