class411
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Post by class411 on Sept 1, 2020 8:36:45 GMT
Surely it's not just the position of bogies/car length but also the position of the doors relative. EG Bank on the Central the double doors often have very little gap but the single car end doors a big gap. I believe the plan is to not have the end doors, meaning doors are further from car ends and therefore closer to the platform? I recall the double doors at Bank often having a v small gap, for example. I don't know if I'm missing something here, but this seems somewhat swings and roundabouts. Surely a straight line (e.g. a railway carriage) meeting a concave curve* will have its closest points at the ends of the line - whereas meeting a convex curve* it will be as you describe ? Or has my brain taken a holiday without telling me? * Relative to the carriage. |
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Post by dm1 on Sept 1, 2020 10:53:55 GMT
When it was decided that S stock would berth beside platforms for level access, rather than overlapping in traditional style, investigations were made into fitting gap-fillers to each train doorway. This must have been based upon the number of platforms that would have required active gap fillers over the system, compared to the number of train doorways. Eventually they went for adjusting track and platforms to reduce the gaps, given worries over reliability of active gap fillers. Ten years since the S stock appeared, reliability will no doubt have improved, but there remains the problem of fitting such equipment within the restricted space beneath tube-gauge trains. Given that such steps (albeit a little shorter than would be required on the tube) have been fitted to trams, I wouldn't have thought space would be that much of an issue. That said, I'm no expert. |
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Post by Chris L on Sept 1, 2020 11:40:45 GMT
When it was decided that S stock would berth beside platforms for level access, rather than overlapping in traditional style, investigations were made into fitting gap-fillers to each train doorway. This must have been based upon the number of platforms that would have required active gap fillers over the system, compared to the number of train doorways. Eventually they went for adjusting track and platforms to reduce the gaps, given worries over reliability of active gap fillers. Ten years since the S stock appeared, reliability will no doubt have improved, but there remains the problem of fitting such equipment within the restricted space beneath tube-gauge trains. Given that such steps (albeit a little shorter than would be required on the tube) have been fitted to trams, I wouldn't have thought space would be that much of an issue. That said, I'm no expert. When S stock was introduced there were a number of incidents where people put a foot in the gap between train and platform. I was working for a maintenance contractor at the time and we had to get crews out to change the lamps in the platform edge lighting in an effort to reduce the number of incidents. |
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Post by Chris M on Sept 1, 2020 12:46:05 GMT
Given that such steps (albeit a little shorter than would be required on the tube) have been fitted to trams, I wouldn't have thought space would be that much of an issue. That said, I'm no expert. Although trams do have lower floors than tube trains, tube trains have less space beneath the floor than do trams. The reason is that both vehicles need to carry much of the same equipment (e.g. compressors) but tube trains mount it below the floor while trams mount it on the roof. |
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Post by croxleyn on Sept 1, 2020 16:59:22 GMT
Of course the middle to end gap ratio will swap depending on the direction of travel if platforms are on opposite sides of the same track pair, or an island platform. And what's to say that the curve remains a constant radius along the platform length? So, each door plate extension will need to be calibrated for each platform.
Does a carriage tip further depending on passenger load? So are strain gauges needed on the carriage suspension to compensate?
What a load of variables to cope with.
And, of course, the plate has to be in place before the doors are open: the video shows almost a second delay, which all slows down a service.
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Post by dm1 on Sept 1, 2020 18:37:16 GMT
Of course the middle to end gap ratio will swap depending on the direction of travel if platforms are on opposite sides of the same track pair, or an island platform. And what's to say that the curve remains a constant radius along the platform length? So, each door plate extension will need to be calibrated for each platform. Does a carriage tip further depending on passenger load? So are strain gauges needed on the carriage suspension to compensate? What a load of variables to cope with. And, of course, the plate has to be in place before the doors are open: the video shows almost a second delay, which all slows down a service. The example I showed uses software that is calibrated to extend the step the right amount for each platform (there's a database of platforms and stopping points etc). Stadler stock uses another approach of just having sensors on the extending step itself that senses the platform edge and stops accordingly, or if the platform is lower. senses the platform below and extends to a length allowing a comfortable step up. Modern train software is capable of handling all those variables and more. A lot of stock does so already (e.g. suspension and braking adjustments based on passenger load/weight). There's no need to reinvent the wheel, just apply existing solutions to the tube environment. As for dwell time, yes, extending the step takes time, but in return you get faster boarding and alighting because there isn't a massive gap/step to negotiate. There might be a small increase in dwell time, but it's nowhere near as large as it would appear at first glance, and I imagine the safety advantages make it well worth it. The better door configuration of the new stock will speed up dwell times in any case. The existence of the gap at all will mean that dwell times will be longer than if it did not exist, so you might as well use the extra time to make it safer. |
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Post by jimbo on Sept 1, 2020 20:33:33 GMT
Given that such steps (albeit a little shorter than would be required on the tube) have been fitted to trams, I wouldn't have thought space would be that much of an issue. That said, I'm no expert. Although trams do have lower floors than tube trains, tube trains have less space beneath the floor than do trams. The reason is that both vehicles need to carry much of the same equipment (e.g. compressors) but tube trains mount it below the floor while trams mount it on the roof. And the air con will need to fit down there too! Might help to have half the cars with no bogies beneath. But there are a lot of doors down the train to fit with gap fillers, leaving little underfloor area for other equipment! |
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Post by dm1 on Sept 1, 2020 20:56:25 GMT
This example claims they need 50mm of space under the door. That isn't all that much. |
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Post by jimbo on Sept 1, 2020 22:37:45 GMT
This example claims they need 50mm of space under the door. That isn't all that much. But presumably insufficient space beneath that for any other equipment, and could the unit take the weight of other equipment anyway? So other equipment must fit away from door areas and bogies. Leaves little area left. |
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Post by aslefshrugged on Sept 2, 2020 7:23:45 GMT
Page 32 of the New Train for London feasibility report suggests that gap fillers would be on the platforms rather than on the trains content.tfl.gov.uk/ntfl-feasibility-report.pdfPage 24 to 27 describes the "air cooling" system - not air conditioning - and managing tunnel temperatures. |
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class411
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Post by class411 on Sept 2, 2020 7:45:03 GMT
Possibly an obvious question, but are the gap fillers intended to be routinely stepped on, or are they simply to stop anyone falling into the gap?
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Post by dm1 on Sept 2, 2020 8:48:30 GMT
Generally they're designed to be routinely stepped on. They're also used for level access for wheelchairs or pushchairs.
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class411
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Post by class411 on Sept 2, 2020 9:34:46 GMT
So there are major safety considerations.
Is there an interlock to ensure that door cannot open until the plate is in place?
Otherwise, after a few years with people expecting to be able to embark and disembark without worrying about a gap, a failed filler could be the cause of a serious incident.
And if there is an interlock, the fillers will need to deploy extremely quickly to avoid an increase in dwell time.
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Post by dm1 on Sept 2, 2020 10:34:32 GMT
I don't know the details, but I assume there is an interlock of some description - perhaps even mechanical. If the step fails for any reason, on mainline stock the door is just locked out of use. That's probably not very desirable on tube stock, but it happens rarely enough that I doubt that's a huge concern (handle it in the same way as a door fault - take the train out of service as soon as practical)
There are safety considerations - but it's been done before. These are solved problems, there's no need to reinvent the wheel.
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Post by countryman on Sept 2, 2020 10:39:45 GMT
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class411
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Post by class411 on Sept 2, 2020 10:46:31 GMT
I don't know the details, but I assume there is an interlock of some description - perhaps even mechanical. If the step fails for any reason, on mainline stock the door is just locked out of use. That's probably not very desirable on tube stock, but it happens rarely enough that I doubt that's a huge concern (handle it in the same way as a door fault - take the train out of service as soon as practical) There are safety considerations - but it's been done before. These are solved problems, there's no need to reinvent the wheel. Yes, but as you say, solved on mainline stock where it might (actually definitely is, in many cases) be considered acceptable to make passengers wait for several seconds before the doors will open. The engineering on the underground would have to be faster, and be capable of a much higher duty cycle. Having the equipment under the platform, rather than on the train would certainly make life easier, but I suspect that things are tighter on the underground and it would also need a safety mechanism to ensure that every filler had retracted before the train started to move. Certainly possible, but definitely not just a simple matter of transferring the technology 'as is'. |
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Post by jimbo on Sept 2, 2020 12:18:22 GMT
Page 32 of the New Train for London feasibility report suggests that gap fillers would be on the platforms rather than on the trains content.tfl.gov.uk/ntfl-feasibility-report.pdfPage 24 to 27 describes the "air cooling" system - not air conditioning - and managing tunnel temperatures. Of course that report was six years back, and further developments may have taken a different approach. |
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Post by Dstock7080 on Sept 2, 2020 12:23:04 GMT
The only gap fillers I have ever seen were on the loop at South Ferry on Line 1 of the New York subway. I don't think it is still in operation, but in this case the 'bridges' came out from the platform to the train. That South Ferry station is now closed, replaced a few years ago. 42nd Street and 14th St./Union Square still retain gap-fille |
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Post by 35b on Sept 2, 2020 14:21:21 GMT
I don't know the details, but I assume there is an interlock of some description - perhaps even mechanical. If the step fails for any reason, on mainline stock the door is just locked out of use. That's probably not very desirable on tube stock, but it happens rarely enough that I doubt that's a huge concern (handle it in the same way as a door fault - take the train out of service as soon as practical) There are safety considerations - but it's been done before. These are solved problems, there's no need to reinvent the wheel. Yes, but as you say, solved on mainline stock where it might (actually definitely is, in many cases) be considered acceptable to make passengers wait for several seconds before the doors will open. The engineering on the underground would have to be faster, and be capable of a much higher duty cycle. Having the equipment under the platform, rather than on the train would certainly make life easier, but I suspect that things are tighter on the underground and it would also need a safety mechanism to ensure that every filler had retracted before the train started to move. Certainly possible, but definitely not just a simple matter of transferring the technology 'as is'. I’m not sure those running Merseyrail would be so casual about dwell times as you suggest. |
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class411
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Post by class411 on Sept 2, 2020 16:42:41 GMT
Yes, but as you say, solved on mainline stock where it might (actually definitely is, in many cases) be considered acceptable to make passengers wait for several seconds before the doors will open. The engineering on the underground would have to be faster, and be capable of a much higher duty cycle. Having the equipment under the platform, rather than on the train would certainly make life easier, but I suspect that things are tighter on the underground and it would also need a safety mechanism to ensure that every filler had retracted before the train started to move. Certainly possible, but definitely not just a simple matter of transferring the technology 'as is'. I’m not sure those running Merseyrail would be so casual about dwell times as you suggest. I didn't suggest anyone was 'casual' about dwell times. I just said that LU would want faster operation than that which is typically accepted on NR. I may be wrong but it does not appear that MerseyRail are looking at anywhere near the 36tph that LU consider viable. |
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Post by 35b on Sept 2, 2020 17:03:00 GMT
I’m not sure those running Merseyrail would be so casual about dwell times as you suggest. I didn't suggest anyone was 'casual' about dwell times. I just said that LU would want faster operation than that which is typically accepted on NR. I may be wrong but it does not appear that MerseyRail are looking at anywhere near the 36tph that LU consider viable. Agreed. But still having to work some congested stations, and where the longer signal sections will mean that extended dwell times will still have knock on impacts. I don’t know if what is being deployed for the 777s will meet LUL aspirations or not, but I wonder if there isn’t a little but of self declared specialness which may not fully be justified. |
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Post by dm1 on Sept 2, 2020 18:48:07 GMT
I wonder if there isn’t a little but of self declared specialness which may not fully be justified. I'm wondering the same thing a little. Especially given that the delay from the step extending is no longer than the delay on the Jubilee line when the ATO system is 'thinking' before the doors open. The Jubilee seems to manage its frequency just fine even with this delay. |
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Post by spsmiler on Sept 3, 2020 20:06:58 GMT
Surely it's not just the position of bogies/car length but also the position of the doors relative. EG Bank on the Central the double doors often have very little gap but the single car end doors a big gap. I believe the plan is to not have the end doors, meaning doors are further from car ends and therefore closer to the platform? I recall the double doors at Bank often having a v small gap, for example. Bank varies according to direction of travel - I would demonstrate this with my pics but proboards no longer allow images which I host to show up here. The text I use on my website [ citytransport.info/Historic.htm ] to describe the situation is... |
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Post by johnlinford on Sept 3, 2020 20:24:56 GMT
Indeed - I was having a temporary lapse in thinking as I tend to only use Bank in one direction on the Central!
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Post by Dstock7080 on Dec 5, 2020 8:05:44 GMT
Interesting recent revelation is that the Piccadilly Line version will have Scharfenberg type 330 couplers and that a coupling adapter will be carried for traditional LT auto-couplers.
Seems these may adopt “2024 Tube Stock” or “24TS”.
A wooden cab mock-up has been already made in Europe with trials and testing of heating and ventilation systems carried out on another mock-up in Buckinghamshire.
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Post by jimbo on Dec 5, 2020 19:10:10 GMT
..... Seems these may adopt “2024 Tube Stock” or “24TS”. ...... But Covid19 delays already look like 2025 entry to service! |
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Post by jimbo on Dec 5, 2020 20:28:03 GMT
Interesting recent revelation is that the Piccadilly Line version will have Scharfenberg type 330 couplers and that a coupling adapter will be carried for traditional LT auto-couplers. ..... This would be the first change since the 1935 experimental tube stock and O/P stocks of the same period, when wedgelock auto-couplers were adopted! I believe a similar coupler was envisaged for S stock, but they reverted to tradition to ease inter-working on the complex sub-surface network. |
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Post by xplaistow on Dec 6, 2020 0:40:36 GMT
..... Seems these may adopt “2024 Tube Stock” or “24TS”. ...... But Covid19 delays already look like 2025 entry to service! It certainly wouldn't be the first time a type of Tube Stock entered service AFTER the year it was named after. |
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Post by t697 on Dec 6, 2020 11:30:23 GMT
But Covid19 delays already look like 2025 entry to service! It certainly wouldn't be the first time a type of Tube Stock entered service AFTER the year it was named after. July 1975 I believe for the Piccadilly line's current 1973TS. Not the worst in this respect though. Step forward 1995TS? |
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Post by rincew1nd on Dec 6, 2020 11:54:51 GMT
Has any tube stock in recent times entered service in the year it was named after?
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