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Post by nig on Jul 1, 2021 12:11:23 GMT
The new stock on pic line will have front and rear cab in tunnels on most of the stations So if the driver needs to leave the cab they'll have to use the J Door and reach the platform via the saloon, as with the 1967ts and 1972ts. That'll be fun at 8:30 on a Monday morning... How will the train be dispatched if CCTV fails? The driver won't be able to look out of the cab door to check the platform on Category Bs and they won't be able to see the stations staff giving a hand signal on Category As. Not too clever... I agree but that's what they want also when running both stock when they first come in there will be 2 diffent stopping marks could get confusing especially if you do new stock first half and 73 stock 2nd half |
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Post by jimbo on Jul 1, 2021 12:24:27 GMT
So if the driver needs to leave the cab they'll have to use the J Door and reach the platform via the saloon, as with the 1967ts and 1972ts. That'll be fun at 8:30 on a Monday morning... How will the train be dispatched if CCTV fails? The driver won't be able to look out of the cab door to check the platform on Category Bs and they won't be able to see the stations staff giving a hand signal on Category As. Not too clever... I agree but that's what they want also when running both stock when they first come in there will be 2 diffent stopping marks could get confusing especially if you do new stock first half and 73 stock 2nd half I think it will be quite clear which stock you are driving! |
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Post by nig on Jul 1, 2021 13:14:43 GMT
I agree but that's what they want also when running both stock when they first come in there will be 2 diffent stopping marks could get confusing especially if you do new stock first half and 73 stock 2nd half I think it will be quite clear which stock you are driving! It will be clear what stock but maybe what stopping mark you use might not be especially if you get distracted by something happening on the platform |
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Post by MoreToJack on Jul 1, 2021 14:06:05 GMT
So if the driver needs to leave the cab they'll have to use the J Door and reach the platform via the saloon, as with the 1967ts and 1972ts. That'll be fun at 8:30 on a Monday morning... How will the train be dispatched if CCTV fails? The driver won't be able to look out of the cab door to check the platform on Category Bs and they won't be able to see the stations staff giving a hand signal on Category As. Not too clever... If the CCTV fails the doors won't be opened. Plenty of occasions where the CCTV fails, or cannot be used for safe dispatch, after the doors have been opened already. Assisted Dispatch can be provided for all manner of reasons. I would suspect a more formal version of the ‘emergency’ practice of having the line’s SCL2 patch into the station CCTV and dispatch the train via Connect radio would be drawn up. No use if there’s a total CCTV failure, of course, but it’s likely in that case that the station would be non-stopped. Worse case scenario, tip out, empty platform and train departs empty in sterile conditions. |
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Post by d7666 on Jul 1, 2021 15:42:33 GMT
With train composition from the referenced article, I guess Picc train numbering may look like this, IMHO they should not have numbers.  If they can irritate the drivers unions by not having drivers (general point, not Picc. specifically related) then why not go the whole way and irritate train spotters by not having numbers. By not having numbers I mean not having sticky transfers displaying arabic numerals, but they can have obfusticted QR codes changed daily only staff can read  |
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Post by d7666 on Jul 1, 2021 15:47:44 GMT
If the CCTV fails the doors won't be opened. Plenty of occasions where the CCTV fails, or cannot be used for safe dispatch, after the doors have been opened already. Assisted Dispatch can be provided for all manner of reasons. I would suspect a more formal version of the ‘emergency’ practice of having the line’s SCL2 patch into the station CCTV and dispatch the train via Connect radio would be drawn up. No use if there’s a total CCTV failure, of course, but it’s likely in that case that the station would be non-stopped. Worse case scenario, tip out, empty platform and train departs empty in sterile conditions. That's a nice idea _ but somebody better ramp up station CCTV reliability and or the comms network reliability over which it communicates to the SCC !!! |
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Post by d7666 on Jul 1, 2021 16:03:54 GMT
Trailer bogies on end cars and their effect on rail head contamination is quite limited where those axles have disc brakes - and I think CRossrail 345s are so.
For the wheelset to "clean" the rail, the wheel tread itself needs cleaning, mulch builds up there too as much as it does on the rail head.
Tread brakes do that cleaning, disc brakes do not. I'm not saying one way or the other what the friction braking on the new stock is, I really have no idea, just commenting the panecea answer about leading unpowered axles is not necessarily what it seems.
One of the reasons BR SR and later incumbents has had an ever increasing increase in adhesion related incidents has been the change from tread braking to disc braking, starting from 508/455s and onwards. Sure the elimination of steam and subsequent allowing increased lineside vegation is an input, disc vice tread brakes is equally important but seldom mentioned.
Even with tread brakes though, take a Thameslink 700, these have tread brakes on motor bogies and disc brakes on trailer bogies. The end cars of all 700s are all motors (FLU = MTMMTT+TTMMTM; RLU = MTMT+TMTM) so all end cars have tread brakes. But the tread brakes are minimal action anyway, 700s friction brakes only cut in on the last 2-3 mph down to stop. They are so little used that even after 5 years service no block or pad had been changed except for a very small number of items failing not directly related to brake cycles. They do just about enough wheel tread scraping to have a cleaning effect.
Thameslink 700s and Crossrail 345s are designed for very similar duty, yet the very fact that these things are done differently kind of proves there are many differing inputs to what axles are or not motored, that that 345s have x1 because of y1 does not mean elsewhere x2 necessarily is the fix for y2.
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Post by MoreToJack on Jul 1, 2021 17:08:13 GMT
Plenty of occasions where the CCTV fails, or cannot be used for safe dispatch, after the doors have been opened already. Assisted Dispatch can be provided for all manner of reasons. I would suspect a more formal version of the ‘emergency’ practice of having the line’s SCL2 patch into the station CCTV and dispatch the train via Connect radio would be drawn up. No use if there’s a total CCTV failure, of course, but it’s likely in that case that the station would be non-stopped. Worse case scenario, tip out, empty platform and train departs empty in sterile conditions. That's a nice idea _ but somebody better ramp up station CCTV reliability and or the comms network reliability over which it communicates to the SCC !!! There’s a reason it’s not officially recognised at the moment, but I have known it done on a few lines. 😬 |
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Post by t697 on Jul 1, 2021 19:41:24 GMT
I think it will be quite clear which stock you are driving! It will be clear what stock but maybe what stopping mark you use might not be especially if you get distracted by something happening on the platform We had this with S stock introduction. The new stock's stop mark is visually completely different to the old stock one. Indeed with platform OPO Mirrors/Monitors for the old stock, one tends to drive so as to align correctly to view the OPO images rather than align to the old stop diamond in the four-foot. Whereas with the new stock having in-cab OPO, the driver drives to align to the new stopping marker specifically - chevron type for S stock and I think 24TS will be using similar, with as far as practicable the same one on shared platforms or clearly marked where not, like the S7, S8 or SS ones on platforms used by both Met and C&H trains. There is typically an issue for some people at some times with breaking the force of habit of driving to the old OPO device instead of the new marker.
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Post by jimbo on Jul 2, 2021 7:35:20 GMT
Out of curiosity, I decided to do some rough calculations to get an estimate of the different car lengths and, by extension, approximate lengths of different formations. Based on the requirement for a 10-11m bogie spacing as stated in the Rail Engineer article I reckon that the trailers will be somewhere around 10m long with the intermediate motors around 14m (the difference will be approximately 2x bogie length). The driving motors are likely to be slightly longer than the intermediate motors due to the extra length of the cabs (as a comparison, S stock driving cars are about 2m longer than the intermediate cars). It is easy to check that these figures are at least close to the actual lengths since this would put a 9-car train at 110m + cabs which would be close to the stated length of 113.7m. Therefore, by either adding or subtracting car lengths I calculate that a 5-car train would be somewhere around 66m while an 11-car train would be about 138m. 66m is a perfect fit for the Waterloo & City since a 4-car 92TS is 65.982m long, however as an 8-car 92TS is only 132.294m the cars for the replacement Central line trains would each need to be about a half metre shorter than on the other lines in order to still fit. This corresponds to the last sentence in the article. These estimates tie in with the figures in the December 2020 Underground News. The new Central line trains may be a little longer than the current trains, up to 134.4m (source NTfL Rolling Stock Technical Specification of 2014 quoted in October 2019 Underground News article "Piccadilly Line New Generation Trains"). The new Central line trains could be the longest on LU, with the current Met & Victoria line trains both about 133m long, the Vic line about 14cm shorter than the Met. ones! |
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Post by spsmiler on Jul 2, 2021 16:58:25 GMT
Surely if the trains used end door cutout or if the end passenger doors were a little further in along the length of the train then more of the back of the train could be in the tunnel, allowing the cab to still be in the station when calling at stations.
I'm not sure which but either Merseyrail or the Tyne & Wear Metro are adopting the second of my options to allow longer trains to be used.
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Post by t697 on Jul 2, 2021 17:18:19 GMT
There's a good number of S stock platforms where the train stops with the front cab off the end of the platform. Not really that much of a problem in practice is it?
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Post by d7666 on Jul 3, 2021 11:40:23 GMT
How does the new Picc stock train length compare with the 9car pre-38 stock Northern line operation that was done just before WW2 (or whenever it was; date is unimportant here) ? I went looking and can't seem to find exact train formation by car type to get the lengths right.
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Post by Dstock7080 on Jul 3, 2021 11:56:03 GMT
How does the new Picc stock train length compare with the 9car pre-38 stock Northern line operation that was done just before WW2 (or whenever it was; date is unimportant here) ? I went looking and can't seem to find exact train formation by car type to get the lengths right. Gives the train formations: www.lurs.org.uk/03%20nov%20NINE%20CARS%20ON%20THE%20NORTHERN.pdf1938 9-car formations: DM-NDM×SNDM-T-NDM-T–SNDM×NDM-DM (SNDM= special NDM with door operating equipment and handbrake |
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Post by d7666 on Jul 3, 2021 13:45:51 GMT
How does the new Picc stock train length compare with the 9car pre-38 stock Northern line operation that was done just before WW2 (or whenever it was; date is unimportant here) ? I went looking and can't seem to find exact train formation by car type to get the lengths right. Gives the train formations: www.lurs.org.uk/03%20nov%20NINE%20CARS%20ON%20THE%20NORTHERN.pdf1938 9-car formations: DM-NDM×SNDM-T-NDM-T–SNDM×NDM-DM (SNDM= special NDM with door operating equipment and handbrake ta, unfortunately the interweb is not playing ball, all I get is a pdf.part file, something is slow or u\s somewhere out there. Back late when I've got it. |
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Post by jimbo on Jul 3, 2021 21:04:34 GMT
How does the new Picc stock train length compare with the 9car pre-38 stock Northern line operation that was done just before WW2 (or whenever it was; date is unimportant here) ? I went looking and can't seem to find exact train formation by car type to get the lengths right. Gives the train formations: www.lurs.org.uk/03%20nov%20NINE%20CARS%20ON%20THE%20NORTHERN.pdf1938 9-car formations: DM-NDM×SNDM-T-NDM-T–SNDM×NDM-DM (SNDM= special NDM with door operating equipment and handbrake A train with no middle cabs, even back then! Not easy to uncouple for maintenance, or deal with defects! |
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DWS
every second count's
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Post by DWS on Jul 4, 2021 18:11:29 GMT
A train with no middle cabs, even back then! Not easy to uncouple for maintenance, or deal with defects! That’s why Cockfosters and Northfields depots are being Upgraded to accommodate the new Piccadilly line trains, the Northern and Jubilee line trains have no middle cabs, but are not uncoupled except in depots. The 8 Car S Stock can be lifted in Neasden depot with out being uncoupled . New trains on the LUL have always seen new solutions to deal with defects etc and so it will be with the 2024 stock on the Piccadilly Line. |
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Post by Chris L on Jul 4, 2021 20:26:03 GMT
A train with no middle cabs, even back then! Not easy to uncouple for maintenance, or deal with defects! That’s why Cockfosters and Northfields depots are being Upgraded to accommodate the new Piccadilly line trains, the Northern and Jubilee line trains have no middle cabs, but are not uncoupled except in depots. The 8 Car S Stock can be lifted in Neasden depot with out being uncoupled . New trains on the LUL have always seen new solutions to deal with defects etc and so it will be with the 2024 stock on the Piccadilly Line. Somebody didn't think ahead at London Overground. Willesden can only lift 4 car trains. |
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Post by 100andthirty on Jul 4, 2021 20:43:23 GMT
Trailer bogies on end cars and their effect on rail head contamination is quite limited where those axles have disc brakes - and I think CRossrail 345s are so. For the wheelset to "clean" the rail, the wheel tread itself needs cleaning, mulch builds up there too as much as it does on the rail head. Tread brakes do that cleaning, disc brakes do not. I'm not saying one way or the other what the friction braking on the new stock is, I really have no idea, just commenting the panecea answer about leading unpowered axles is not necessarily what it seems. One of the reasons BR SR and later incumbents has had an ever increasing increase in adhesion related incidents has been the change from tread braking to disc braking, starting from 508/455s and onwards. Sure the elimination of steam and subsequent allowing increased lineside vegation is an input, disc vice tread brakes is equally important but seldom mentioned. Even with tread brakes though, take a Thameslink 700, these have tread brakes on motor bogies and disc brakes on trailer bogies. The end cars of all 700s are all motors (FLU = MTMMTT+TTMMTM; RLU = MTMT+TMTM) so all end cars have tread brakes. But the tread brakes are minimal action anyway, 700s friction brakes only cut in on the last 2-3 mph down to stop. They are so little used that even after 5 years service no block or pad had been changed except for a very small number of items failing not directly related to brake cycles. They do just about enough wheel tread scraping to have a cleaning effect. Thameslink 700s and Crossrail 345s are designed for very similar duty, yet the very fact that these things are done differently kind of proves there are many differing inputs to what axles are or not motored, that that 345s have x1 because of y1 does not mean elsewhere x2 necessarily is the fix for y2. Braking and cleaning the railhead are two very complex subjects, made even more complex when ATP/ATO systems which require wheelset based odometry. Having the end bogies as trailer bogies and using the friction tread brakes to clean the wheels is a perfect solution if the braking is set up to give the friction brakes some work to do. As d7666 says, modern trains are set up to do very little friction braking. Indeed, that's why a 100mph EMU in the form of the class 700 "gets away with" tread brakes on motor cars; just as well really as there is no space for disc brakes on those inside frame bogies. The 2024 tube stock will have tread brakes and, with permanent magnet motors, the friction brakes are likely to do less work than on S stock. LU will, therefore, have to work out how to keep the friction surfaces in good order. Northern, Jubilee and all S stock, have a routine built into the trains such that they do a friction only brake application for a couple of stops on every run to keep the wheel/friction surface in good order. Achieving good adhesion between the wheel and the rail is not generally something that can be delivered by the train alone. Keeping the lineside clear of foliage is the first requirement, followed by the operation of Rail Adhesion Trains. The final ingredient is the use of sanders which are controlled by the wheelslide protection system. Sanders, are, these days, fitted to virtually all but the very oldest of main line trains and to S stock. Properly optimised sanders can deliver excellent braking in poor conditions. Final point, adhesion is affected by the ride quality of the trains. Modern trains ride better than older trains. The lateral motion of wheels on rails helped to clear leaf contamination, but I don't think anyone would want to swap the ride of a modern EMU for that of a 4-SUB! |
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Post by jimbo on Jul 5, 2021 5:29:02 GMT
Thanks to d7666 for reminding us of earlier 9-car tube trains on the Northern line. These trialed with standard stock, but then ordered 1938TS. I believe these trains were all similar length cars, so probably just over 148m, compared to possible Central line trains of 134.4m replacing current 8-car trains. The former 9-car trains were two cars longer than tunnel platforms. Pre War they seemed to work OK, but were dropped during hostilities and never restarted. One wonders if this would work today with walk-through trains and public address warnings making things easier. They could leave a single car in the tunnel at each end of trains.
The June 2017 Underground News review of historic District line timetables revealed that for many years the District ran a few 10 cars trains from East Ham to Whitechapel, where they split for the shorter tunnel platforms. Presuming these cars were of similar size to their replacements, therefore I calculate at around 160m, they were even longer!
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Post by d7666 on Jul 5, 2021 12:56:24 GMT
The 2024 tube stock will have tread brakes and, with permanent magnet motors, the friction brakes are likely to do less work than on S stock. LU will, therefore, have to work out how to keep the friction surfaces in good order. Northern, Jubilee and all S stock, have a routine built into the trains such that they do a friction only brake application for a couple of stops on every run to keep the wheel/friction surface in good order. Isn't it by location rather than by run ? At least on S-stock. Again this is outside my area, but I am sure I read something recently about certain stations on the current 4LM CBTC are always approached on friction brakes. Farringdon or Blackfriars ISTR (stick in mind as they are my interhcange to Thameslink) might be one of them. There is the usual TLA acronym for this function but I can't remember it right now. |
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Post by d7666 on Jul 5, 2021 15:54:34 GMT
We are definitely into digression: having now brought BR SR 4Sub into the thread, the subject of railhead and wheelsets for traction adhesion as well as braking adhesion comes up.
It is often alleged that unpowered axles at outer ends of EMU aid traction adhesion with motored axles in inner vehicles.
But the BR SR example of 4Sub > 508 > 455 tends not to fully agree with that.
4Sub (and 4EPB) were all MTTM with a Bo2 motor coach at the outer ends. They were [partly] replaced by 508s first which were also MTTM but a BoBo motor coach at outer ends, and disc braked. 508s suffered from far worse braking issues than Sub\EPB largely on account of their disc brakes - but they still had their motor coaches at the outer ends. Then 455s - those are TMTT, with one BoBo motor coach as an inner vehicle; and these have the same braking issues, and [were***] more inclined to slip.*** Even with the alleged help from leading unpowered axles, they still slipped badly. With two sets multipled together, the situation is not much better (indeed it can be worse). My travel experience on commuting on Thameslink is that the AC motored 700 is far far more surefooted than the DC motored 319s, and that is down to motor characteristics not powered\unpowered axles. If I were commuting from Amersham and not Luton, I'd probably be saying the same thing about S and A stocks.
*** thats was 455s with DC motors; they now have AC motors and /ought/ to be performing better; a series wound DC motor once it begins to slip actually feedbacks conditions to amplify slipping not reduce it (that's why they appear to slip madly) but an asynchronous AC motor is self correcting. Permanent magnet motors (per the new Picc. stock) are as yet a mystery to me I've not found time to dig into them, but anyway the AC v. DC motor in slip conditions applies every bit as much to S stock v. A|C|D stock, and e.g. 95 96 to earlier tube stocks.
End of digression, I hope, befored excommunication for doing it cuts in.
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Tom
Administrator
Signalfel?
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Post by Tom on Jul 5, 2021 16:36:10 GMT
Isn't it by location rather than by run ? At least on S-stock. Again this is outside my area, but I am sure I read something recently about certain stations on the current 4LM CBTC are always approached on friction brakes. Farringdon or Blackfriars ISTR (stick in mind as they are my interhcange to Thameslink) might be one of them. There is the usual TLA acronym for this function but I can't remember it right now. It is indeed by location, and the TLA you're looking for is actually an FLA - FOBA (Friction Only Brake Application). Aldgate East, Baker Street, Wood Lane, and Temple were all FOBA sites at one point, though I'm not sure what the current list is. |
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Post by d7666 on Jul 5, 2021 16:47:16 GMT
FOBA thats the one .... for some reason I did remember it began FO....  as one wit translated that as flipping off brake application or similar terminology  I didn't want to confuse with other FO... XLAs where FO mean fibre optic. What would we do without these acronymns. Or making up alternatives. |
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class411
Operations: Normal
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Post by class411 on Jul 5, 2021 17:23:47 GMT
[OFFTOPIC]
Interesting to see that the railway industry has run out of unique TLA's and are now using ETLA's (extended three letter acronyms - or, usually, more properly, ETLI's [extended three letter initialisms]).
[/OFFTOPIC]
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Post by 100andthirty on Jul 5, 2021 18:44:37 GMT
FOBA thats the one .... for some reason I did remember it began FO.... as one wit translated that as flipping off brake application or similar terminology I didn't want to confuse with other FO... XLAs where FO mean fibre optic. What would we do without these acronymns. Or making up alternatives. This is true for the Sub surface lines where the Seltrac and the traction equipment have some sort of communication. On Jubilee and Northern another means had to be found and although the aim was for the friction only applications to be made in the open, it doesn't always work out that way. |
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Post by t697 on Jul 6, 2021 7:19:58 GMT
The former 9-car trains were two cars longer than tunnel platforms. One wonders if this would work today with walk-through trains and public address warnings making things easier. They could leave a single car in the tunnel at each end of trains. I suspect it would at least lead to another thread here like the one criticising the S stock arrangement at Baker Street platform 5...! And in any case it is more difficult to move through a busy Tube car than an S stock car. |
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Post by Dstock7080 on Jul 7, 2021 19:05:21 GMT
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Post by philthetube on Jul 7, 2021 20:29:23 GMT
I think it will be quite clear which stock you are driving! It will be clear what stock but maybe what stopping mark you use might not be especially if you get distracted by something happening on the platform You can also say that to all the bus drivers who have gone under low bridges in double deckers, also anyone who is old enough to remember when cars did not all have indicator stalks on the same side will tell you that is was very easy to turn on the wipers instead of indicating, the brain often doesn't work in the way which you would expect it to. |
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Post by capitalomnibus on Jul 13, 2021 22:46:10 GMT
Thanks to d7666 for reminding us of earlier 9-car tube trains on the Northern line. These trialed with standard stock, but then ordered 1938TS. I believe these trains were all similar length cars, so probably just over 148m, compared to possible Central line trains of 134.4m replacing current 8-car trains. The former 9-car trains were two cars longer than tunnel platforms. Pre War they seemed to work OK, but were dropped during hostilities and never restarted. One wonders if this would work today with walk-through trains and public address warnings making things easier. They could leave a single car in the tunnel at each end of trains. The June 2017 Underground News review of historic District line timetables revealed that for many years the District ran a few 10 cars trains from East Ham to Whitechapel, where they split for the shorter tunnel platforms. Presuming these cars were of similar size to their replacements, therefore I calculate at around 160m, they were even longer! If they had 9 car trains on the Northern line, I am sure there was no selective door opening, so did doors open on the carriages that were stuck in the tunnels? |
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as one wit translated that as flipping off brake application or similar terminology 
