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Post by Tom on Aug 12, 2023 10:46:58 GMT
Quite simply every line has a capacity in terms of trains per hour. The pinch point is the location where the signalling has the lowest capacity, and becomes the limiting factor for the overall service that can be operated. Once you try to run more trains than the line can handle, it becomes inevitable that a queue of trains will form trying to get past the pinch point.
From memory Kings Cross WB cannot handle more than 24tph whereas the rest of the line can manage a bit higher (around 27tph, I think).
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Post by Tom on Aug 11, 2023 18:48:40 GMT
I agree with Chris - it's almost certainly passenger throughput. The Victoria line resignalling (to 36tph) has highlighted that at certain key stations, such as Victoria, it's impossible to clear the platforms from one train before the next arrives. I expect that in coming years, the passenger throughput through a station will become the limiting factor on capacity, rather than rolling stock or signalling, in many more places.
With regard to Holborn it cannot be signalling capacity that restricts things, as Holborn isn't the pinch point. On the WB Piccadilly the pinch point is Kings Cross.
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Post by Tom on Jul 30, 2023 20:00:18 GMT
I'm going to guess at between Dagenham East and Elm Park.
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Post by Tom on Jul 27, 2023 6:42:31 GMT
Westbourne Park for the main.
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Post by Tom on Jul 26, 2023 20:09:58 GMT
[People who use wheelchairs also prefer paper travel cards - especially if they have self-propelled wheelchairs because they often need to stop and rest their arms during the journey. Too often this need (to stop and rest) sees them breach Oyster journey time limits. Has there been anything to suggest this is actually the case, or is it something you perceive could be a problem? I don't think I've ever heard of this being a problem before - possibly because in most cases, those wheelchair users living in Greater London would have the use of a Disabled Persons Freedom Pass.
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Post by Tom on Jul 25, 2023 15:59:27 GMT
Of course, that doesn't mean that it's even been considered for LU (or any other railway). That's the point I was getting at; if the introduction of such technology is realistically in the pipeline for LU.
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Post by Tom on Jul 24, 2023 21:22:00 GMT
This will only change when 'be here' ticketing is introduced, because it will follow (track) us through our entire journey and be able to charge for actual travel. Whether passengers will welcome that degree of surveillance / tracking remains to be seen. Is this something that is on the horizon or a figment of your imagination?
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Post by Tom on Jul 24, 2023 20:50:15 GMT
Used to be 70 north of Harrow North Junction to Amersham. Short of recalculating every overlap I'm not sure what they were signalled for, but I think they might not be considered adequate by today's requirements.
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Post by Tom on Jul 23, 2023 19:26:03 GMT
assuming LUL does not have an agreement with Chiltern for someone to install CBTC in their fleet. As my learned colleague d7666 has posted, there's no agreement to fit CBTC onto any main line stock. Even if there was, the agreement would not be with Chiltern but with the Rolling Stock Leasing Company who actually owns it. ]Some of the Chiltern Turbos still regularly reach 75mph and the GWR turbos still regularly reach 90mph. But if that is the case then why are the Chiltern Railways services also limited to 60mph on LUL tracks? Braking distances and overlaps for 60 mph ? Most of the signalling in that area would have been designed to the 1955 overlap formula - a 60mph overlap on level gradient would work out at about 476m and for 70mph would be nearly 650m. Using the current 2008 formula would result in a slightly shorter overlap. Others who are more experienced in overlap calculation than I am might suggest that some of the existing overlaps are probably a little short for 60mph today, but part of the justification in a multi-aspect area could be that it is unlikely a driver will fail to react to previous cautionary aspects and trip at line speed. (Though obviously this did happen with the incident at Chalfont a few years ago.) The braking distances from the first cautionary aspect to a red tend to be quite generous and would appear to have been calculated on a very low brake rate appropriate for steam traction, possibly with some additional allowances for brake build-up along the train (the standard Newton's laws of motion equations assume deceleration rate is constant and instantaneous). There are, of course, other factors which would need to be considered before permitting an increase in speed - track is designed for specific speeds, particularly around curves and any increase in line speed would need to be assessed for things like cant.
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Post by Tom on Jul 13, 2023 18:28:13 GMT
The lower image is East Acton. Not sure about the upper.
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Post by Tom on Jul 10, 2023 19:22:06 GMT
One of those situations where Companies House is a very useful website!
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Post by Tom on Jul 10, 2023 18:39:01 GMT
The outdoor sections of the Central line no longer need the air main; I don't know if it's still kept pressurised though.
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Post by Tom on Jul 10, 2023 18:25:32 GMT
Thanks for that I did a search but that company did not come up mostly overseas companies. KGM became KME (Kent Modular Electronics) in 1990. They're still trading - I remember them supplying new monitors for the control desks at Baker Street in the early 2000s. www.kme.co.uk/
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Post by Tom on Jul 10, 2023 18:21:48 GMT
That's exactly what they were!
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Post by Tom on Jul 9, 2023 17:38:17 GMT
I wonder if it might be Croxley, but I'm not 100% sure.
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Post by Tom on Jul 8, 2023 11:33:35 GMT
A Acton Main Line, B Roding Valley.
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Post by Tom on Jul 4, 2023 21:06:14 GMT
blue handrails visible in reflection and took it to be Piccadilly line, also cable runs confirmed this, just looked a Google maps to locate similar buildings and knowing level of the line to adjacent roads. I often use the cable run to guide me too. I had a feeling it was the Uxbridge branch, but wasn't sure where!
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Post by Tom on Jun 19, 2023 19:53:10 GMT
Oh yeah, I can see the TTC signs now!
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Post by Tom on Jun 19, 2023 16:31:42 GMT
I think No. 4 might be 30th Street, Philadelphia.
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Post by Tom on Jun 16, 2023 18:36:53 GMT
ALARP - As low as reasonably possible. Practicable, not possible.
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Post by Tom on Jun 7, 2023 14:33:27 GMT
Inset 1 = West Bromwich Town Hall. I should have known that one, considering my grandparents lived on the same road...
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Post by Tom on May 30, 2023 19:49:32 GMT
At Shepherd's Bush Market, there's no way that for 99.9% of passengers it could take 3 minutes to get from the entrance to the platform. Lifts. The transit time has to be for the reasonably slowest individual. There aren't any lifts (or a footbridge) at Shepherd's Bush Market. Just a set of stairs from each platform down to the ticket hall.
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Post by Tom on May 23, 2023 14:57:48 GMT
Looks like Willesden Green, but I could be wrong.
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Post by Tom on May 12, 2023 17:02:16 GMT
My personal thought is that it is Sub-Surface, as the Northern Line had NMAs (Northern Migration Areas), But the Jubilee TBTC migration didn't have JMAs did it ? No, they were simply known as J1 to J5. I have confirmed today via two independent sources that the S does indeed stand for SSR. It's only taken me four and half years!
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Post by Tom on May 11, 2023 20:17:26 GMT
I think the main is South Ealing.
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Post by Tom on May 8, 2023 18:00:26 GMT
There couldn't have been many as High Street Ken was mostly underground. The last survivor was FRED1510 which wasn't far from Earl's Court.
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Post by Tom on May 6, 2023 22:35:05 GMT
some of those acronyms expanded: SMA = Signal Migration Area What the 'S' stands for is debatable. I've heard Signalling, System, Sub-Surface, and Seltrac, all of which could be perfectly valid. My personal thought is that it is Sub-Surface, as the Northern Line had NMAs (Northern Migration Areas), though I probably ought to check what the contract documents say it is. In the old days we would have simply called it Stage 1, 2, 3 etc., which would have been a lot more straightforward!
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Post by Tom on May 5, 2023 21:13:53 GMT
Is the derailment of an engineering train within the boundaries of the depot something that the RAIB would investigate? It might not be something the RAIB would investigate but it's probably notifiable. In quite a few instances they appoint an Accredited Agent to undertake assessments and preserve evidence whilst the Investigator is on their way to site. I have also known of incidents which are notified but they and the ORR don't initially get involved, but keep a close eye on the situation and have the right to intervene if they feel appropriate later.
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Post by Tom on Apr 30, 2023 21:41:58 GMT
As not every escalator has the same vertical rise (and not every rise will be a multiple of a specific dimension *), and at least one rises at a different angle from the standard, there will always be some bespoke parts. That's not to mean that every part is bespoke; though I would expect Kone to have a 'Heavy Duty' range for customers such as LU. Yes it would be better to be open and honest but to say "unavailable because the supplier was bought out and the new owners promptly removed this design from their project catalogue" is a bit of a mouthful. I'd also suggest your statement is equally misleading. Kone bought out APV in 1998. By 2013 (some 15 years later) it was getting harder to get APV Parts. Fifteen years in an industry like this is hardly prompt - it's moving at a glacial pace! A 1998 mobile phone would have been obsolete within five years, never mind fifteen. And is anyone still using Windows 98 now? * - Yes, I'm aware it will be a multiple of a very small dimension such as 1mm, but let's be realistic.
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Post by Tom on Apr 27, 2023 19:20:02 GMT
Maybe Tom knows the SIL number; I sure do not; if the ATO kit is SIL4, then AIUI it has to be independently verified by a body like Lloyds. Bearing in mind that SelTrac is an integrated ATO/ATP/ATS train control system, it'll be SIL4.
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