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Post by joshua on Apr 9, 2022 17:40:10 GMT
Yes but the Met is a very different railway. That said, you have got me wondering, how many passing loops would be needed for Chesham to have a 10 minute service (alternate trains to London and Watford via the North Curve)? oh and if the second platform at Chesham was reinstated would it be long enough? I would be very surprised if the second platform at Chesham was long enough for an S stock. It's been a while since I was there, but in my mind it's about the same length as the bay platform at Chalfont & Latimer. Could you rebuild the bridge just to the South of Chesham to permit the platform extension of the of the currently disused bay platform to be able to take a 10 coach train? Could you also a passing loop in about halfway along the line so that you could improve service frequency? |
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Post by joshua on Apr 9, 2022 17:42:40 GMT
Fitting CBTC over the current signalling so that drivers no longer drive according to the light signals, but press start buttons so that the train drives itself according to the light signals, does appear to be a pointless use of money. But wouldn't there be some improvement in run times, in that the response to a signal clearing would be measurably more prompt, trains would follow a standard performance between stations, and with control of train speed some speed restrictions could be eased. Granted negotiations with NR could take some time. And perhaps any improvement may still be too small to justify the cost. It's already been said above but perhaps wasn't explained in enough detail..... The idea of overlaying CBTC onto the District line's Network Rail signalled sections has nothing to do with improving run times or frequency of the train service; that's impossible as long as there's dual running with national rail rolling stock. It's purely about having one single method of train protection for S stock - the CBTC system - rather than the complication of retaining tripcock protection and the associated costs, risks & issues that come with that. For starters there's the need to continue the maintenance and testing regime for the tripcock equipment fitted on trains and trackside. Operationally it means we retain permanent boundaries between the CBTC & legacy tripcock railway and that in turn creates a world of issues if a train fails to correctly switch between the two signalling systems. Retaining tripcock protection on Network Rail signalled track means we retain the three minute time delay after tripping which is a nuisance on Network Rail. It also adds an additional piece of stock defect handing knowledge required to be retained by drivers (not just signalling related but when dealing with air defects for example). Are CBTC and ETCS compatible? |
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Post by Tom on Apr 9, 2022 20:05:32 GMT
But wouldn't there be some improvement in run times, in that the response to a signal clearing would be measurably more prompt, trains would follow a standard performance between stations, and with control of train speed some speed restrictions could be eased. Granted negotiations with NR could take some time. And perhaps any improvement may still be too small to justify the cost. There wouldn't be in theory - as the signalling is designed to support a specified headway where a signal clears to it's least restrictive aspect just before a driver reaches the point at which they have to shut off and brake for a cautionary aspect. In practice there would be some potential to improve response and run times when services are disrupted or a train is waiting for a signal to clear - but the signalling is designed so that at the specified headway trains aren't detained. There would also be a removal of the individuality between drivers. However, that's not where we are. With regard to your last but one sentence, I can't say any more than I already have: the gap in requirements between the two organisations (Thales and NR) was too great to be overcome. It wasn't simply a case of negotiations taking more time. |
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Post by Tom on Apr 9, 2022 20:07:24 GMT
Are CBTC and ETCS compatible? No, but they have similar principles. |
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Post by Tom on Apr 9, 2022 20:09:27 GMT
I would be very surprised if the second platform at Chesham was long enough for an S stock. It's been a while since I was there, but in my mind it's about the same length as the bay platform at Chalfont & Latimer. The second platform at Chesham is very short with the station buildings at the end. It was used for steam locos in the past. It could (and did) take a 4 car train of 'A' stock, but that was pre-Moorgate. I would expect the requirements for overrun distances now to be prohibitive. |
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Post by Chris M on Apr 9, 2022 20:33:33 GMT
Could you rebuild the bridge just to the South of Chesham to permit the platform extension of the of the currently disused bay platform to be able to take a 10 coach train? Could you also a passing loop in about halfway along the line so that you could improve service frequency? With enough money almost anything is possible. An S8 stock train is 134 metres long according to Wikipedia. Based on air photos the base of the water tower at the head of the bay platform is about 145 metres from the bridge, so an S8 would fit without changes to the bridge if it is wide enough for 2 tracks (I don't know, but the air photo on google shows a train passing under it that is definitely off centre so it's plausible) and you are prepared to accept an overrun of only about 9 metres. At Stanmore the air photo shows trains stopped approximately 18 metres from the buffer face, which is in turn about 20 metres from the end of the track. S stock have more momentum than 96 stock (being both longer and heavier) so it seems exceedingly unlikely that 9 metres would be acceptable. The distance from the signal box to the bridge is similar so that offers no advantages. This means that demolition and replacement of the bridge will almost certainly be required. The air photo suggests this would not be particularly difficult structure to design and/or build. The working timetable says that it is 6.2 km from Chalfont & Latimer to Chesham, so in theory a passing loop should be about 3.1 km from each end, this is about 100 metres east of the footpath crossing east of Blackwell Stubbs Wood. The railway here is on a fairly high embankment about 300m as the crow flies from the nearest road so not the best place to build new infrastructure. About 500m west of that, so 3.7km from C&L / 2.5km from Chesham the railway passes over Hollow Way Lane on a shallower embankment and nearby is in cutting/level. If you were to build an intermediate station on the branch this is where you would build it, as there is large residential area that would be better served than by either Chesham or Amersham station (Google says about 25 minutes walk from here to Amersham station or 40 minutes to Chesham). There is also a small amount of industry to the north that would be within walking distance (if pavements were improved). TfL don't have the money (which they don't) and if they did they would probably not want to spend it outside London. So someone else would have to fund it (Bucks county council most likely), but would it be value for money? The extra stop would add running time, and given the unequal lengths of single track either side timetables would need to have padding here for reliability. Putting a station there would increase both costs and benefits, probably more the latter but whether significantly more I don't know. |
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Post by joshua on Apr 9, 2022 21:28:48 GMT
I prefer the idea of rebuilding the bridge at Chesham. Could the pass loop be long enough that if a train was a minute late it did not cause the other train to need to slow down for the train? The idea of an extra station does sound a good idea.
Quote removed - this is a reply to the previous post in the thread so there wasn't really a need to quote. If you need to quote, please do selectively rather than quoting complete posts. Thanks, Tom.
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Post by Tom on Apr 9, 2022 21:47:11 GMT
Folks, we're starting to drift into (F)RIPAS territory here. Can we stick to discussion about what's actually happening (or was supposed to happen), rather than how we might do things if money was no object, please?
Now, on the subject of junctions to and from the Chesham branch, in the early days of 4LM there was a plan to relocate the junction to/from the Chesham branch much further towards the actual divergence. What I can't remember was if the existing junctionwork at Chalfont was supposed to be subsequently removed, therefore moving the problem further north and away from a station (which would have been a convenient point to wait for a move off the single line) or if it was going to be retained, effectively as a long loop.
In any case the more radical plans from that workstream were quietly dropped.
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Post by joshua on Apr 10, 2022 9:38:36 GMT
How far have they got with resignalling the SSR and what parts are going to be done?
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Post by Dstock7080 on Apr 10, 2022 10:12:34 GMT
How far have they got with resignalling the SSR and what parts are going to be done? all of that information is contained within this thread but: done are: Hammersmith-Latimer Road Latimer Road-Paddington (H&C) Paddington H&C-Euston Square/Finchley Road/Paddington (District) Euston Square-Monument/Stepney Green Monument-Sloane Square Sloane Square-Fulham Bdwy/Barons Court/Olympia/Paddington still to do: Stepney Green-Becontree Becontree-Upminster Finchley Road-Preston Road Preston Road-West Harrow/Moor Park Moor Park-Amersham/Chesham West Harrow-Uxbridge Barons Court-Stamford Brook Fulham Bdwy-East Putney. 😅 |
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Post by joshua on Apr 10, 2022 10:44:42 GMT
Are line speed being raised as part of SSR Upgrade and if so by how much?
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Post by joshua on Apr 10, 2022 11:45:05 GMT
Now, on the subject of junctions to and from the Chesham branch, in the early days of 4LM there was a plan to relocate the junction to/from the Chesham branch much further towards the actual divergence. What I can't remember was if the existing junctionwork at Chalfont was supposed to be subsequently removed, therefore moving the problem further north and away from a station (which would have been a convenient point to wait for a move off the single line) or if it was going to be retained, effectively as a long loop. In any case the more radical plans from that workstream were quietly dropped. Why was relighting the Chesham branch line junction not done? |
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Post by Deleted on Apr 10, 2022 22:14:07 GMT
Are line speed being raised as part of SSR Upgrade and if so by how much? Yes some areas the speed is increasing along with the acceleration rate of the train will also increase. |
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Post by Deleted on Apr 10, 2022 22:14:39 GMT
Now, on the subject of junctions to and from the Chesham branch, in the early days of 4LM there was a plan to relocate the junction to/from the Chesham branch much further towards the actual divergence. What I can't remember was if the existing junctionwork at Chalfont was supposed to be subsequently removed, therefore moving the problem further north and away from a station (which would have been a convenient point to wait for a move off the single line) or if it was going to be retained, effectively as a long loop. In any case the more radical plans from that workstream were quietly dropped. Why was relighting the Chesham branch line junction not done? Cost |
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Post by joshua on Apr 11, 2022 11:49:29 GMT
Are line speed being raised as part of SSR Upgrade and if so by how much? Yes some areas the speed is increasing along with the acceleration rate of the train will also increase. What will the new line speeds be? |
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Post by Deleted on Apr 11, 2022 18:02:52 GMT
This is down to several factors there is no one speed for everywhere. The system is very accurate and can set limits from 5mph upwards in 5mph increments. Yes CBTC uses kph to set limits before anyone says anything but being simple I do the conversion to mph as that is what I’m used too
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Post by joshua on Apr 13, 2022 13:29:12 GMT
What is the maximum speed limit which the computer can let the train run on the section between Baker Street & Finchley Road? |
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Post by Dstock7080 on Apr 13, 2022 14:24:30 GMT
What is the maximum speed limit which the computer can let the train run on the section between Baker Street & Finchley Road? 55mph 1171m north of Baker Street platform 2 to 1758 north of Baker Street platform 2 |
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Post by alpinejohn on Apr 13, 2022 14:34:59 GMT
What is the maximum speed limit which the computer can let the train run on the section between Baker Street & Finchley Road? The speed targets on any section of track are basically a function of any infrastructure limitations which are in turn determined by the Permanent Way people and are then reflected in the programming. |
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Post by d7666 on Apr 13, 2022 16:05:23 GMT
What is the maximum speed limit which the computer can let the train run on the section between Baker Street & Finchley Road? 55mph 1171m north of Baker Street platform 2 to 1758 north of Baker Street platform 2 I always find this sort of thing amusing - (a) a speed in imperial units over a distance in metric units (b) a speed stated with coarse granularity (mph; but km/h would be the same effect) compared to a distance stated with fine granularity (metre; but yard would be the same effect). Yes, I have heard all the reasons and explanations why all before; nonetheless it just amuses me. Not challenging the data, nor it's presentation, it is the way these things are in the real world, just it is amusing to OCD. It is akin to going to a pub where you'd expect beer listed as sold in pints i.e. rounded to the nearest 1/2 pint and charged to the nearest 5 pence, but find it served in multiples or fractions of 0.568261 litre. |
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Post by Dstock7080 on Apr 13, 2022 19:05:24 GMT
55mph 1171m north of Baker Street platform 2 to 1758 north of Baker Street platform 2 I always find this sort of thing amusing - (a) a speed in imperial units over a distance in metric units Not challenging the data, nor it's presentation, it is the way these things are in the real world, just it is amusing to OCD. Yes, apologies I slipped again forgetting it had previously been proven that CBTC is kph and that the information provided for train staff is misleading. |
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Post by spsmiler on Apr 13, 2022 20:13:35 GMT
Are line speed being raised as part of SSR Upgrade and if so by how much? Yes some areas the speed is increasing along with the acceleration rate of the train will also increase. Will Baker Street - Amersham (and return) journey times be faster than was offered by A stock trains which were designed for a 10mph higher speed limit? (70 mph) I am thinking of like for like in terms of calling patterns, which I accept might be slightly difficult because northbound fast trains no longer non-stop Wembley Park and Harrow-On-The-Hill). Also, another impediment is the junction where the fast / main line and local line join between Moor Park and Rickmansworth. When the route was rebuilt with four tracks BR express trains still ran between Marylebone and Manchester and London Transport installed higher speed points (50 mph I believe for trains to / from the local lines). But a few years ago as part of the 'modernisation' of the SSR this junction was rebuilt in a way that requires trains to travel significantly more slowly. This is in addition to line speed reductions from above 70mph in recent decades. (I retained both quoted messages as I see them both as being directly relevant to my question) |
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Post by capitalomnibus on Apr 20, 2022 1:12:16 GMT
How far have they got with resignalling the SSR and what parts are going to be done? all of that information is contained within this thread but: done are: Hammersmith-Latimer Road Latimer Road-Paddington (H&C) Paddington H&C-Euston Square/Finchley Road/Paddington (District) Euston Square-Monument/Stepney Green Monument-Sloane Square Sloane Square-Fulham Bdwy/Barons Court/Olympia/Paddington still to do: Stepney Green-Becontree Becontree-Upminster Finchley Road-Preston Road Preston Road-West Harrow/Moor Park Moor Park-Amersham/Chesham West Harrow-Uxbridge Barons Court-Stamford Brook Fulham Bdwy-East Putney. 😅 The sections that have not been done, does the driver drive in standard manual mode then. |
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Post by Dstock7080 on Apr 20, 2022 3:23:03 GMT
The sections that have not been done, does the driver drive in standard manual mode then. In “tripcock mode” yes. |
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Post by jimbo on May 8, 2022 20:02:15 GMT
May 7, 2022 21:23:03 GMT 10 Dstock7080 said: There are amendments to MET WTT342, District WTT152 on 16 May to take account of the Jubilee Line and National Rail timetable change.- Mon 6 June Waterloo & City reverts to WTT7, full M-F service but not weekends
Mon 27 June Northern new WTT59 introduced, enhanced services to Battersea and Night Tube services reintroduced
Mon 18 July MET new WTT343 and Piccadilly new WTT60 introduced, MET for Piccadilly service changes and Piccadilly for reintroduction of stabling at South Harrow(!) and Night Tube services
(provisionally Sun 11 September MET new WTT344, H&C new WTT37 and District new WTT153) link
Presume SSR lines are provisional, depending on new signalling commissioned to Becontree, and these will include new run times for entire Circle and Hammersmith & City lines, together with District line from Becontree to Earl's Court area. Met. central area run times were adjusted in the previous timetable. The District will then only await the resignalling east to Upminster before commissioning moves on to the Met. |
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Post by Dstock7080 on May 9, 2022 3:40:03 GMT
Presume SSR lines are provisional, depending on new signalling commissioned to Becontree, and these will include new run times for entire Circle and Hammersmith & City lines, together with District line from Becontree to Earl's Court area. Met. central area run times were adjusted in the previous timetable. The District will then only await the resignalling east to Upminster before commissioning moves on to the Met. WTT37 WTT153 are for runtime adjustments after SMA 4 / 5, SMA 6 commissioning will be after 11 September. |
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Post by Dstock7080 on May 9, 2022 9:06:05 GMT
Hearing from my Test Train colleagues that during this weekends SMA 6/7 testing that trains were comfortably achieving 100kph (interpreted as 62mph in train cabs), between Stepney Green and Upminster.
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Post by spsmiler on May 9, 2022 23:51:25 GMT
Hearing from my Test Train colleagues that during this weekends SMA 6/7 testing that trains were comfortably achieving 100kph (interpreted as 62mph in train cabs), between Stepney Green and Upminster. I would welcome experiencing this for myself! No doubt most other passengers would too - except for the Luddites for whom quickness and faster journeys is an anathema and who think that 20 mph (30km/h) is sufficient speed for urban travel. |
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Post by gigabit on May 13, 2022 11:21:33 GMT
Hi there.
I note at East Putney a board saying "due to a temporary fault the board indicators are wrong". It has been "temporary" for well over a year and a half!
What is happening here?
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Post by Deleted on May 13, 2022 11:52:40 GMT
Which way?
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