metman
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Post by metman on Oct 16, 2020 17:31:09 GMT
I doubt tooting is an option as the time to de-train passengers would create a significant backlog with a high frequency service. Some reversals at Golders Green and Finchley Central/East Finchley (if they ever make the required modifications at the latter) might allow an improved frequency in the central areas although the regular users to Edgware and Barnet might be unhappy!
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Post by quex on Oct 16, 2020 17:39:16 GMT
I've just been reminded that in 'Rails Through the Clay' it's mentioned that the peak timetable from July 1912 had 44tph. Granted, this was before combination with the C&SLR, and the timetable included a variety of non-stopping services, but I still find it amazing that such a service was possible.
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Post by t697 on Oct 16, 2020 17:44:41 GMT
I've often wondered about those claims and others of about 40tph on the Bakerloo I think it was. Possibly it was with very short trains? Or purely theoretical with ideal driving and ideal passengers and dwell times? Or even both directions, so 22tph one direction?
Anyone seen a Working Timetable that shows 40 - 44tph?
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Tom
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Post by Tom on Oct 16, 2020 19:05:04 GMT
The late Mike Horne was pretty sure the Northern line did it in the 1920s, though with some signalling arrangements that would not be acceptable today.
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metman
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Post by metman on Oct 16, 2020 19:51:42 GMT
I guess the 20s still had short trains, gate stock and certainly fewer users so perhaps shorter dwell times? The Hampstead tube had the terminal loop at Charing Cross and later Kennington so I imagine with no waiting times all sorts may have been possible.
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Chris M
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Post by Chris M on Oct 17, 2020 2:00:01 GMT
Quite possibly they weren't that strict about detrainments either which would speed up matters. Although with gate stock and a member of staff at the end of every car it probably wouldn't have taken that long anyway.
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Post by spsmiler on Oct 17, 2020 11:18:02 GMT
I doubt tooting is an option as the time to de-train passengers would create a significant backlog with a high frequency service. Some reversals at Golders Green and Finchley Central/East Finchley (if they ever make the required modifications at the latter) might allow an improved frequency in the central areas although the regular users to Edgware and Barnet might be unhappy! I am curious, what are the 'required modifications' at East Finchley? As an aside, would not an enhanced rush hour service to Mill Hill East help? eg:, perhaps a train every 7 - 10 minutes? Even if stepping back is required. |
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Post by alpinejohn on Oct 17, 2020 12:39:18 GMT
I doubt tooting is an option as the time to de-train passengers would create a significant backlog with a high frequency service. Some reversals at Golders Green and Finchley Central/East Finchley (if they ever make the required modifications at the latter) might allow an improved frequency in the central areas although the regular users to Edgware and Barnet might be unhappy! I am curious, what are the 'required modifications' at East Finchley? As an aside, would not an enhanced rush hour service to Mill Hill East help? eg:, perhaps a train every 7 - 10 minutes? Even if stepping back is required. As trains move away from the central area passenger numbers tend to thin out, so the idea of turning short some services provides an attractive way of increasing frequency in the central section of the line. A big problem with this idea is finding places where you can do this service reverse without stacking up trains following behind - which would pretty much negate any benefit of turning services short. The ideal solution would entail some stations being provided with an additional platform and pointwork to give direct access to a dedicated reversing platform from both directions. So if we want to turn short a Northbound service the train could be quickly routed into this dedicated reversing platform allowing the points to be swiftly switched back to allow the following service to access the normal Northbound platform without delay. This ideal set up would then allow ample time to detrain anyone still sleeping on the service being reversed whilst the driver switches ends. Sadly the current East Finchley track layout was not designed with service reversal in mind despite having 2 island platforms. The pointwork is actually a legacy of the original "Northern Heights" plan with the outer tracks served by tube trains into london, with the central pair of tracks intended for services from the abandoned high level route and access to the former Highgate Woods depot(now Highgate Sidings and Wellington sidings. The most critical missing element to facilitate reversing at East Finchley is to reinstate the removed pointwork which used to exist just after trains emerge from the tunnel to allow a Northbound train to be routed into either Platforms 1 and 2 - with similar additional pointwork installed to allow trains to depart southbound from either platform 3 and 4 rather than just platform 4 at present. The problem is best understood if you look at the Carteo map here linkCurrently any attempt to reverse trains at East Finchley is hideously complicated as follows.. (1) Northbound train arrives platform 1 + platform staff then detrain any remaining passengers (whilst delaying following Northbound trains) (2) train departs northbound until fully clear of points (Still delaying following Northbound services (3) driver changes ends and reverses into platform 2. (once in platform 2 the Northbound services can resume use of platform 1) (4) driver changes ends and drives into the siding at the North end of platforms 2/3. (5) driver changes ends and drives into platform 3. (6) driver changes ends and waits for signallers to find a suitable gap in Southbound services (7) driver departs platform 3 Northbound onto the Southbound mainline until clear of the points (now delaying all following southbound trains) (8) driver changes ends and proceeds into platform 4 to form the next southbound service. As you can see, East Finchley is not a brilliant place to reverse services North - South. Rather than messing with East Finchley it is probably far better to turn trains at Archway where there is already reversing pointwork and a siding just north of the platforms. OK because there is no dedicated reversing platform available, it still holds up following trains whilst people are de-trained but with adequate alert platform staff the delay is usually quite short.
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Post by countryman on Oct 17, 2020 15:51:33 GMT
What is wrong with Finchley Central? Arrive at platform 1 or 2 depending on the destination of following train. Forward into the siding. Reverse to platform 3 and away. This assumes the siding is sufficiently long.
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Post by scheduler on Oct 17, 2020 16:06:24 GMT
Today's signalling would not support those level of service on either Bakerloo or Northern.
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Post by alpinejohn on Oct 17, 2020 19:49:26 GMT
What is wrong with Finchley Central? Arrive at platform 1 or 2 depending on the destination of following train. Forward into the siding. Reverse to platform 3 and away. This assumes the siding is sufficiently long. There is nothing wrong with using Finchley Central to turn services. However it is a lot further out compared with turning services at Archway - simply put you should get more benefit to central area service levels by turning services nearer to the centre of town. Whilst they sometimes do that move to reverse services at Finchley Central, it seems Mill Hill is the preferred option as it avoids any potential delays to following services whilst detraining passengers in platforms at Finchley Central. I am pretty sure that a bit like travelling around the Kennington Loop - trains are not allowed to carry passengers over non-approved trackwork - so whilst I have no doubt that occasionally a sleeping passenger will making a brief visit to the siding leading toward Mill Hill - it is not officially allowed, hence turning trains at Finchley Central would require extra platform staff time to check carriages are empty and coach by coach close the doors using the porter buttons before such moves can commence. |
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Post by North End on Oct 17, 2020 22:05:27 GMT
What is wrong with Finchley Central? Arrive at platform 1 or 2 depending on the destination of following train. Forward into the siding. Reverse to platform 3 and away. This assumes the siding is sufficiently long. There is nothing wrong with using Finchley Central to turn services. However it is a lot further out compared with turning services at Archway - simply put you should get more benefit to central area service levels by turning services nearer to the centre of town. Whilst they sometimes do that move to reverse services at Finchley Central, it seems Mill Hill is the preferred option as it avoids any potential delays to following services whilst detraining passengers in platforms at Finchley Central. I am pretty sure that a bit like travelling around the Kennington Loop - trains are not allowed to carry passengers over non-approved trackwork - so whilst I have no doubt that occasionally a sleeping passenger will making a brief visit to the siding leading toward Mill Hill - it is not officially allowed, hence turning trains at Finchley Central would require extra platform staff time to check carriages are empty and coach by coach close the doors using the porter buttons before such moves can commence. Closing up using the porter buttons is the result of the Liverpool Street incident some years ago. Kennington Loop is the exception, and this seems to be a case of corporate memory loss, as it’s really no different to Liverpool Street in that someone could walk through the cars. |
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Tom
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Post by Tom on Oct 17, 2020 23:44:39 GMT
Closing up using the porter buttons is the result of the Liverpool Street incident some years ago. Kennington Loop is the exception, and this seems to be a case of corporate memory loss, as it’s really no different to Liverpool Street in that someone could walk through the cars. Exactly. There are two issues here which are often confused: On a line equipped with fixed block signalling, you must not carry passengers over a route controlled by a shunt signal (without appropriate authority), due to the lesser standard of route locking which is provided. On any line, you must check that all passengers have alighted from a train being taken out of service, to prevent an overcarried passenger from panicking and trying to leave the train via the car end doors. |
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Post by North End on Oct 18, 2020 0:26:17 GMT
Closing up using the porter buttons is the result of the Liverpool Street incident some years ago. Kennington Loop is the exception, and this seems to be a case of corporate memory loss, as it’s really no different to Liverpool Street in that someone could walk through the cars. Exactly. There are two issues here which are often confused: On a line equipped with fixed block signalling, you must not carry passengers over a route controlled by a shunt signal (without appropriate authority), due to the lesser standard of route locking which is provided. On any line, you must check that all passengers have alighted from a train being taken out of service, to prevent an overcarried passenger from panicking and trying to leave the train via the car end doors. There seems to be some further corporate memory loss when it comes to the ATP lines, as the general view amongst operating staff is that passengers can be carried over any route where the train has a TBTC target point. However (from conversations I’ve had!) the signal department seem to disagree, as their view is that the facing point locking is the same as it was under the old signalling, which seems to be confirmed by the fact that there’s an instruction that passengers must not be taken north from East Finchley platform 3, which used to be a shunt move. Obviously there’s now some of the newer procedures which blur all this. |
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Post by jimbo on Oct 18, 2020 3:16:27 GMT
With new tube trains costing £16m each, short-workings can cut the cost of new fleets. NLU2 looked at turning at East Finchley to save the 6½ minute return trip to Finchley Central, where there is only a single reversing siding north of the platforms. Trains would have used a new connection to the middle northbound platform where they could take time off the running line to clear passengers. They would then have worked up to the existing reversing siding before coming back to the middle southbound platform and then over a new connection to the running line. However, even this was too inefficient and it was then proposed to add a scissors crossover on the High Road bridge to allow reversing trains to enter either middle platform, and to return southbound directly from there. Archway only offers a single reversing siding with detrainment on the running line, and safe entry to the dead-end tunnel could also slow following trains, unsuitable for perhaps 100 second headways. Of course, with virtually free new trains from Jubilee line rejects the economic balance of all this new trackwork may now have changed.
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Post by toby on Oct 18, 2020 8:02:03 GMT
Archway only offers a single reversing siding with detrainment on the running line, and safe entry to the dead-end tunnel could also slow following trains, unsuitable for perhaps 100 second headways. As I understand it the same is planned for West Hampstead. Is that reversing siding long enough for quicker entry? |
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metman
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Post by metman on Oct 18, 2020 8:42:29 GMT
I thought West Hampstead had modifications a few years ago?
It would be a shame if something is not done at East Finchley there is certainly wasted capacity there.
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Post by superteacher on Oct 18, 2020 8:55:05 GMT
Although a disruptive move, can trains not reverse north to south via the crossover?
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metman
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Post by metman on Oct 18, 2020 12:38:57 GMT
I guess because with the planned/hoped for frequency it would create delays?
The scissors at East Finchley would probably be the best option.
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Tom
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Post by Tom on Oct 18, 2020 14:57:17 GMT
I thought West Hampstead had modifications a few years ago? The points and crossings to the siding were renewed, but there is little scope for improving run-in speed due to the length of the overrun. |
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Post by jimbo on Oct 19, 2020 0:23:28 GMT
I thought the point of renewing the points at West Hampstead was to ease the speed restriction over them. Also those centre sidings (inc. Willesden Green and Wembley Park) once accepted 8-car Met trains when required. Has any member recent experience of the speed into Archway siding? Is it done in TBTC or manual driving? What is the overrun length like at the far end? This was once a 12-car overrun siding when the line terminus. The extension took a new route to leave the current siding. Financial economies may not permit a new track layout at East Finchley, and perhaps Archway plus Finchley Central will have to do instead.
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Post by North End on Oct 19, 2020 2:22:11 GMT
I thought the point of renewing the points at West Hampstead was to ease the speed restriction over them. Also those centre sidings (inc. Willesden Green and Wembley Park) once accepted 8-car Met trains when required. Has any member recent experience of the speed into Archway siding? Is it done in TBTC or manual driving? What is the overrun length like at the far end? This was once a 12-car overrun siding when the line terminus. The extension took a new route to leave the current siding. Financial economies may not permit a new track layout at East Finchley, and perhaps Archway plus Finchley Central will have to do instead. Been a long time, but if my memory is right it’s 10 mph into Archway, and there is some space beyond the stopping position, perhaps a couple of cars lengths (there’s certainly more room than Tooting Broadway which is extremely tight). As with all running sidings both ATO and PM are available. There was an issue that the stopping mark was in the wrong place for TBTC, but I presume this has long been sorted. |
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Post by alpinejohn on Oct 19, 2020 8:40:54 GMT
The underlying rationale for splitting the line was to increase service levels - especially through the central sections where services cannot keep up with demand.
Whilst trackwork at Camden Town already allows either central area route to serve either Northern Branch it still creates delays and backing up of trains. For instance even if the timetable is carefully designed to avoid delays at the junction, passenger boarding times at stations along the route will vary, and this may mean northbound trains on both routes heading for Edgware arrive at the same time. Hence one train will need to be held outside the station (delaying following services on that branch) whilst the other proceeds into the Camden Town station, and can only follow into the platform once the preceding train has cleared the station block.
Splitting the lines simply substitutes these "hidden" in tunnel delays with longer platform dwell times caused if increased numbers of passengers need to change trains at Camden Town.
The other concern is that in peak hours passengers wanting to board at inner stations like Tufnell Park & Kentish Town who often find arriving town bound services are so full that no one at all is able to board. A friend said things were so bad that they used to regularly travel north to Highgate to stand a chance of catching a southbound service into town.
Once COVID is resolved then almost inevitably commuting levels will surge and once again turning short a few peak hour services at Archway will really show its value for those frustated inner area passengers.
If the siding at Archway is indeed super-long then perhaps one cheap and cost effective investment would be to modify the siding to allow faster access to the siding. 10 mph max for an empty train movement does seem low whilst mainline trains can switch tracks at 60mph+.
By clearing the Northbound route quicker, it should reduce any delays to following services and potentially allow more services to be turned short.
Having more rolling stock may help a little bit (assuming you have enough drivers) but even with a glut of trains Camden Town will remain the real constraint on service levels.
Ultimately what if anything happens will be determined by the bean counters assuming TFL does not find an unexpected pot of gold.
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Tom
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Post by Tom on Oct 19, 2020 18:03:04 GMT
If the siding at Archway is indeed super-long then perhaps one cheap and cost effective investment would be to modify the siding to allow faster access to the siding. 10 mph max for an empty train movement does seem low whilst mainline trains can switch tracks at 60mph+. All well in theory, but as Archway is a tunnel siding, that's a lot of expensive tunnelling alterations for a handful of trains that reverse there, very few of which are timetabled. Does it meet the cost/benefit test? Probably not. |
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Tom
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Post by Tom on Oct 19, 2020 18:05:21 GMT
I thought the point of renewing the points at West Hampstead was to ease the speed restriction over them. Whilst I wasn't involved in West Hampstead, the usual reason for track renewal work (plain line or P&C) is track condition. |
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Post by jimbo on Oct 20, 2020 4:27:00 GMT
I thought the point of renewing the points at West Hampstead was to ease the speed restriction over them. Whilst I wasn't involved in West Hampstead, the usual reason for track renewal work (plain line or P&C) is track condition. The Jubilee Line World Class Capacity Project Feasibility report - April 2014 - said that remodelling at West Hampstead would provide enhanced reliability of service, since relaying the points for faster running would allow scheduled reversing there. This was done in advance of delivery of additional trains to provide an interim service enhancement. We are still awaiting the additional trains, originally a batch to split with the Northern line, but now proposed to replace the Jubilee fleet for transfer to meet Northern line needs. |
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Post by jimbo on Oct 22, 2020 19:09:52 GMT
The other concern is that in peak hours passengers wanting to board at inner stations like Tufnell Park & Kentish Town who often find arriving town bound services are so full that no one at all is able to board. A friend said things were so bad that they used to regularly travel north to Highgate to stand a chance of catching a southbound service into town. Hope they had a zone 3 ticket if challenged enroute! |
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Post by spsmiler on Oct 22, 2020 19:51:53 GMT
The other concern is that in peak hours passengers wanting to board at inner stations like Tufnell Park & Kentish Town who often find arriving town bound services are so full that no one at all is able to board. A friend said things were so bad that they used to regularly travel north to Highgate to stand a chance of catching a southbound service into town. Hope they had a zone 3 ticket if challenged enroute! With PrePay / Pay As You Go (PAYG) Oyster surely all that matters is that the person 'touched in' at the start of their journey? As far as I am aware the roving ticket inspectors cannot tell if the passenger has done this - or in any other way backtracked on their journey. However, if the passenger has a zonal Travelcard, then 'ouch'! They have been caught. |
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Post by superteacher on Oct 22, 2020 20:51:21 GMT
The other concern is that in peak hours passengers wanting to board at inner stations like Tufnell Park & Kentish Town who often find arriving town bound services are so full that no one at all is able to board. A friend said things were so bad that they used to regularly travel north to Highgate to stand a chance of catching a southbound service into town. Hope they had a zone 3 ticket if challenged enroute! With PrePay / Pay As You Go (PAYG) Oyster surely all that matters is that the person 'touched in' at the start of their journey? As far as I am aware the roving ticket inspectors cannot tell if the passenger has done this - or in any other way backtracked on their journey. However, if the passenger has a zonal Travelcard, then 'ouch'! They have been caught. A bit of a grey area is this. They have no intention of leaving the system “out of zone”. Would a revenue inspector turn a blind eye? |
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Post by grumpycat on Oct 23, 2020 1:09:11 GMT
I'd say keep as is now with peak time trains as is however redo the points so it can handle the 30tph I think points are still needed to get all Northern line station connections without changing over
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