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Post by t697 on Dec 24, 2019 9:13:46 GMT
Oh, it's past 0900 now, I'll go for Ealing Common, train just left platform 2 and entering the depot. Oops, beaten to it I see!
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Post by t697 on Dec 24, 2019 9:09:56 GMT
You can believe it or not; I’m only an Instructor Operator but I would have thought that was qualification enough. I’m not going into a full technical explanation but it is a deliberate design. Traction current is fed via the pick up shoes on a DM (driving motor) car to a box known as the ACM (auxillary converter module). There are two ACM’s per S stock train; one on each DM car. The ACM’s distribute power around various circuits and one of those is a direct feed to the compressor on the same DM car. It is because the compressors are directly fed from the ACM on the same car that at least one of the DM cars must be on traction current in order to produce air. Thanks for the confirmation. I wonder what advantage this arrangement gives, clearly of such magnitude as to outweigh the very real risk of 'gapping'? Whatever you think about the design policy, S stock is not really different in this respect to most LUL trains from 1973TS onwards. Trains formed from single ended units of 1973TS, D78 stock and then the 95TS, 96TS, 09TS and S stock have two compressors and need the DM car local to the compressor to have a traction supply so that the compressor can run. Current rail layouts are as far as practicable laid out so both DM cars don't get gapped at the same time, but this is not always possible. Maybe alterations will be possible here, I don't know. After a signalling and track modification a couple of Christmases ago at Earl's Court something similar happened and the conductor rails were modified to prevent it.
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Post by t697 on Dec 23, 2019 19:02:36 GMT
Changed from Thameslink to the Underground at Farringdon this morning. Took the opportunity to check the ticket machines on both sides of Cowcross Street. All the machines have an A-Z destination finder on the touch screen. Once selected I typed East and East Croydon appeared in the list of stations on the right of the screen. Once selected you are able to select the type of ticket you require. On the way home I saw that the Turnmill Street entrance has two ticket machines of the narrow type. No reason to believe that they will not have the A-Z destination finder. That's how I used the A-Z selector and typed as well. Must have been some temporary system malfunction, I tried two machines.
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Post by t697 on Dec 21, 2019 23:19:57 GMT
Harrow and the Chiltern route were long ago part of the planned Crossrail route. So we are not quite off topic yet but it must be close!
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Post by t697 on Dec 21, 2019 23:06:58 GMT
At least in Farringdon it seems that it is only not possible at a certain entrance. However at Harrow - I don't think you can buy a rail ticket to go beyond Amersham. Only the new entrance on Cowcross St at Farringdon seems to have ticket machines for NR destinations. The CW Clark style building entrance to the LUL station doesn't. And as others have confirmed in this thread, the human ticket seller in the new entrance ticket office appears to be working for Thameslink and much more competent than the machines! So I assume LUL staff would direct you to that new entrance from the LUL ones if you asked about tickets to NR destinations.
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Post by t697 on Dec 21, 2019 22:55:52 GMT
Do we know the reason for yesterday evening's failed train incident? Was it CBTC related? I believe it involved the 1734 Aldgate to Watford service and couldn't be moved for over an hour north of Baker Street? I was on the 1754 Aldgate to Amersham service which eventually got to Farringdon about 1850. We were then asked to leave the train as it was the Controller's intention to hold the train between Farringdon and King's Cross for approx. 20 mins as trains were slowly worked along the Inner Rail station to station. I caught Thameslink to West Hampstead, Jubilee Line to Wembley Park, a Neasden Depot starter to Harrow and yes....re-joined the Amersham train I had left at Farringdon an hour or so earlier! There was also a signal failure later on yesterday evening at Wembley Park suspending the service south to Aldgate which may have been a repeat of a failure that happened yesterday morning similarly suspending the service south of Wembley Park. Train understood to be in PM got gapped in the 10mi/h section leaving Baker St 2 NB apparently. There are queries as to why this is limited to 10mi/h since it wasn't with old signalling. Looks like improvements to come...
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Post by t697 on Dec 21, 2019 13:51:58 GMT
Surprised Driver(s) didn't notice 8 cars instead of 7 displayed on the TCMS (Train Control Management Screen). In fact the TCMS would surely be the ideal place for a safeguard... If it threw up a warning when a Line/Destination incompatible with the train configuration was selected then that would be hard to miss. There was originally a requirement to run S7 trains in passenger service from Baker St to Harrow and back for stabling at Neasden, rather than running as empty stock which is the current actual practice. For some but not all of these trips there were H&C Trips in the TCMS/CIS. For others, Met Trips would be selected. There has been no move to make the available CIS Trips be software interlocked with the train length. I'm not sure it would have stopped this particular incident. As the train runs from Neasden as empty stock, the driver may likely have selected 'Not in Service' rather than whatever Circle trip it becomes at Baker St. Indeed since the train is handed from Met to C&H driver, the Met driver wouldn't necessarily know its Circle destination specifically. So while such a software feature could have flagged it to the C&H driver, the train would already be at Baker St and need to be dealt with anyway.
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Post by t697 on Dec 21, 2019 13:41:17 GMT
Just to clarify, a procedure existed at Hammersmith to reverse an S8 under legacy signalling if absolutely necessary (it never was). I don’t know if this has been transferred to CBTC but I would imagine so (the logic is the same, just with a different way of working). Either way, there’s a few options available at Edgware Road and all would be preferred, as would reversing at High Street. I think the CBTC is programmed so it can't grant a Movement Authority for an S8 to proceed west of the reversing berth just west of Edgware Road, except for it to go onwards via High St Ken for moves towards Ealing etc. So to go to Hammersmith (H&C) it would have to be in Restricted Manual all the way and there's a restriction saying not to do that! Reverse in Baker St 6 or at Edgware Road.
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Post by t697 on Dec 21, 2019 13:31:45 GMT
Ah, maybe I should have selected zone 6 then. There are no maps or line diagrams at the ticketing area to guide anyone to know that. If me as an LU/TfL employee doesn't know that, how is the average Jack or Jill supposed to know?
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Post by t697 on Dec 21, 2019 9:29:31 GMT
I do not know the full situation here, as I've never thought to look, but it does sound very wrong that passengers might be unable to buy the correct ticket before they travel. Surely they should (at a minimum) be ticket machine capability for potentially possible fares from here, in the same way that quieter stations may have a ticket machine that can sell tickets to all sorts of destinations (even for trunk InterCity journeys that involve a change of train en route) and pre-paid ticket collections but not a 24/7 staffed ticket office I did actually buy a ticket! Two staffed windows. One had someone who seemed to be on training and not selling tickets. I was front of queue but it still took 5 minutes as the other customer had some long involved purchase of multiple tickets for multiple family members on multiple journeys it seemed. 5 minutes to buy a ticket then dashed to platform, just caught the train and in East Croydon 20 minutes later, no problem. I was just puzzled by the odd and limited choice of destinations from the machines. I tried typing in East Croydon, Croydon - not recognised on either of the two machines I tried. Always offered me Earlsfield...
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Post by t697 on Dec 19, 2019 19:04:49 GMT
Not sure whether this is the right place. Move it if not! I had cause to travel from Farringdon to East Croydon today. I went in via the new entrance on Cowcross St and went to buy a ticket. There are only 3 ticket machines and they don't accept East Croydon as a destination despite there being a frequent and direct train service between the two stations without changing trains. It doesn't seem to be that the machines are 'TfL/LUL destinations only' as they were very keen to offer me a ticket to Earlsfield instead. What's the story here I wonder? Something specifically against Thameslink?
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Post by t697 on Dec 17, 2019 20:40:24 GMT
Not sure on Upminster, but yes for Ealing Common. S8s have covered pretty much the entirety of the SSR network - I’m not sure about east of Whitechapel, and they definitely haven’t been to Hammersmith (too long). They have also been to Northfields depot and to Rayners Lane via North Ealing. S8 permitted to Upminster as empty stock as alternative wheel turning facility. The trip to Rayners and back via North Ealing was with an S7. Clearance proving in case any had to be moved that way for taking to Ruislip and Derby for ATC fitting after SMA2 precluded non fitted train going via Baker St. In the actuality of course all trains had completed their Derby trips well before SMA2.
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Post by t697 on Nov 30, 2019 12:01:53 GMT
Whilst we are on the topic of Parsons Green, are there any track layout changes due there in advance of CBTC rollout? Changes at PG are due but whether they will be implemented before CBTC I doubt, as the Embankment/Westminster and Barking changes are not happening before. They will sever the link from eastbound platform into 21-22 roads, and vice-versa. Trains to/from 21-22 will have to use westbound platform. A new diamond crossover further west of the station will allow access from Wimbledon into westbound platform and 28 road, trains could also start from eastbound platform to Wimbledon. I don't think those changes currently have funding do they?
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Post by t697 on Nov 29, 2019 18:59:24 GMT
B looks like Park Royal but I expect others have already spotted it!
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Post by t697 on Nov 29, 2019 18:57:14 GMT
Or even a 'schematic'.
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Post by t697 on Nov 22, 2019 19:53:17 GMT
The LUL Sub Surface Railway ATC roll out has shown more people the longer delay from the train stopping until the doors open, about a second longer than in the 'legacy' areas it seems. Not good, but today I had cause to make a journey on a London Overground class 378 train. I timed from wheels stop until door release and it was regularly taking 6 - 7 seconds. This seems a very long time indeed. 10 stops and you've wasted a whole minute or more with the train stopped and nothing useful happening. Is there a technical reason or something procedural? Or a bit of both?
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Post by t697 on Nov 21, 2019 6:16:02 GMT
3rd stage of JLE opening linked new and old so you could travel between these two places without changing trains.
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Post by t697 on Nov 20, 2019 19:29:51 GMT
Is the concrete at Bermondsey? 3rd stage of Jubilee line Extension opened 20 years ago today.
20 years! OMG
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Post by t697 on Nov 19, 2019 19:23:50 GMT
Yes, that probably gets us to the track or signals answers. I don't recall how much overrun space there is at Cockfosters but maybe with a good ATC you could reverse 24tph there and 12 at Arnos middle road. And if the ATC or more particularly the ATC/train integration isn't that good, then you might need an extra platform. Need to be able to use the available wheel/rail adhesion to get good run-in and run-out times. So that will also affect whether new crossovers allowing faster speeds through them are part of the solution to get the performance wanted.
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Post by t697 on Nov 18, 2019 16:15:28 GMT
Perhaps the final targets for Picc line are also relevant here. As others have mentioned, reversing 36tph off two platforms is fairly easy with Train Operator Stepping Back, but if you don't want to use Stepping Back you probably need 3 platforms. But if the final target is to eliminate Train Operators would you build another platform in the interim? I am not up to date with end goals, or is that GOAs?
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Post by t697 on Nov 14, 2019 20:44:18 GMT
Well there's a challenge! Had to go off and look things up. The motoring only PCMs like A stock, 1959/62TS etc. and also the 1967TS and 1972TS have two stages of field weakening available. Not always used though. For example 1962TS on the Central line didn't. The first stage (FS1) is under notching relay control switched by an auxiliary contact on the last camshaft step, after full parallel been reached. The second stage (FS2) is switched in under control of a separate current sensing relay called the Field Shunt Relay. This drops out at a lower current than the normal Rate 2 notching relay setting. This scheme seems to have two justifications; 1. It made the control circuits easier to implement. 2. The lower setting of FSR allows for quite a big step in field strength without an excessive current peak when FS2 closes.
C stock, 1973TS and D78 stocks have all field weakening steps under notching relay control, sequenced from camshaft auxiliary contacts. 1973TS and D78 stock have up to three stages of field weakening, C stock had two. 1973TS is actually set up to only use the first stage (FS1). D78 stock used only the first two stages.
Only the 1972TS and 1973TS now stopping this thread being more correctly in 'Historical' I suppose. :-)
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Post by t697 on Nov 14, 2019 20:29:16 GMT
Clapham Common the only one on the City & South London?
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Post by t697 on Nov 13, 2019 6:04:33 GMT
The pic on the left can only be Stepney Green the worst station I feel on the line +1. The WB platform I think.
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Post by t697 on Nov 11, 2019 19:10:16 GMT
Yes it's been added to assist fault finding and routine maintenance tasks.
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Post by t697 on Nov 10, 2019 15:44:06 GMT
Maybe Headstone Lane for B?
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Post by t697 on Nov 10, 2019 15:37:22 GMT
A - Stonebridge Park? Oops, should have refreshed the page before posting...
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Post by t697 on Nov 8, 2019 7:53:26 GMT
Hello, Just trying to get my history around how weak field has been applied on the Underground. The odd old one - F stock 1920 had a "tapped field" relay that was activated when a certain speed was reached in notch 9. As far as I can gather from the forums here everything from 1938 stock onwards had weak field available for d.c. motors that was only engaged by raising the weak field flag. (I can see the case for the Bakerloo going to Watford Junction.)
If this continued on all stock with d.c. motors, was the last stock to have this in the form described the 1992 tube stock? There is a very good explanation for the D78 stock on trainweb. It is basically saying that "flag down" acted as a speed limiter and cut off power to the motors above 30 mph. Was this same thing true for all stock including the A60 stock - which would make some sense for speed limits in central London - or was the A stock able to achieve a higher speed than that with the flag down? Thanks Darwin
1. I'm sure the F stock tapped field would have been switched at a certain motor current, not a speed control which would have been very difficult with 1920s tech. That said, it would be a certain speed assuming constant line supply voltage (which does vary though!). 2. 1983TS was the last with d.c. series motors. The present 1992TS equipment has d.c. chopper control with separately excited fields. On the old signalling the Central line ran at one setting throughout on the 1962TS and the 1992TS had a software controlled 'interrunning' performance to match that. It may have involved an element of motor field control. With ATC signalling throughout, the full performance characteristic software is used. Maximum speed is then enforced by the signalling as appropriate to the section of line etc. 3. The 30mph (approx) mentioned for D stock was the automatic coasting speed when the weak field flag switch was down. With coasting cut out the train could go faster even with the weak field flag down. The automatic coasting speed setting was higher with the weak field flag up. I think 1983TS also had the automatic coasting feature but no LUL stocks before D78 had it.
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Post by t697 on Nov 2, 2019 18:17:41 GMT
The JL interior Refurb didn't include any seat refurbishment I understand. But I agree the end of car perches have been allowed to get into very poor condition.
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Post by t697 on Oct 25, 2019 5:07:35 GMT
Main pic - Pinner
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Post by t697 on Oct 22, 2019 14:26:04 GMT
To be honest they look a bit of a bodge. Yes indeed, it looks like one may be Arial and the other Arial Condensed, but both could have been the same. And with it turning out to be Willesden Green, suspicion may still fall on TLL who often ignored requirements to use Johnston.
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