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Post by spsmiler on Oct 8, 2019 21:36:04 GMT
Some really wide speed fluctuations under CBTC! Why would this be? Track / infrastructure condition? Indeed there are, mostly because of the ballast to slab track conversion works that have given a much improved track form and that in turn has facilitated significant speed uplifts on the straight single bore sections. Only remaining sections of bull head track on this section now are at Swiss Cottage and Lord's. At the time of of that graph being drawn up, I believe there were some intervention vectors being tested out which might explain the erraticity to/from Finchley Road in particular. The track condition in that area is capable of supporting existing speed limits (30 SB & 25 NB I think) so I'm concluding that its more to do with a migration boundary being close by. But in general, the quality of track in this area is fantastic compared to what it was a few years ago, testimony to the massive speed uplift in places. Am I right in thinking that the northbound locations where the CBTC speeds are lower than previously still have bullhead rails and when these areas have the bullhead rails replaced and the track beds rebuilt the speeds will rise even more? Slower speeds when travelling in to the London terminus is nothing new - I can recall journeys which even 30 years ago were timetabled to be a minute longer when travelling west into Liverpool St (BR) than when travelling east away from here. |
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Post by norbitonflyer on Oct 9, 2019 6:22:56 GMT
Slower speeds when travelling in to the London terminus is nothing new - I can recall journeys which even 30 years ago were timetabled to be a minute longer when travelling west into Liverpool St (BR) than when travelling east away from here. This may be the reason, but the public timetable also includes some "recovery time" between the last two stops of most trains, so you expect the scheduled time between the penultimate and last stop of an inbound service to be longer than in the other direction. |
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Post by goldenarrow on Oct 9, 2019 12:47:25 GMT
Indeed there are, mostly because of the ballast to slab track conversion works that have given a much improved track form and that in turn has facilitated significant speed uplifts on the straight single bore sections. Only remaining sections of bull head track on this section now are at Swiss Cottage and Lord's. At the time of of that graph being drawn up, I believe there were some intervention vectors being tested out which might explain the erraticity to/from Finchley Road in particular. The track condition in that area is capable of supporting existing speed limits (30 SB & 25 NB I think) so I'm concluding that its more to do with a migration boundary being close by. But in general, the quality of track in this area is fantastic compared to what it was a few years ago, testimony to the massive speed uplift in places. Am I right in thinking that the northbound locations where the CBTC speeds are lower than previously still have bullhead rails and when these areas have the bullhead rails replaced and the track beds rebuilt the speeds will rise even more? For the stretch over the Regents Canal towards Lord's, probably, I think it's only new ballast that went in there. There is a sharp kick on the NB just before Lord's so I'm not complaining. If that is remedied in the future, then it would be reasonable to expect it to mirror the SB. The significant dip in speed just before Finchley Road is at the location of the shunting berth for the crossover at Swiss Cottage. CBTC will for now effectively treat a NB train at Finchley Road as an absolute block section so that muted speed may have been mitigation for increased dwell times in the early days as I don't recall such slow speeds being used now that T'Ops are unassisted. I fully expect the crawl from Finchley Rd SB to vanish just as it did from Wood Lane when 0.5 whent live. There are other little discrepancies that may have been accentuated because of the way I've compared the speed limit. The CBTC speeds are much more precise to the metre whilst I have omitted the manual speed considerations for approach control/timed section signals so its very much approximate locations. I think apart from those niggles, I think the MET is maxed out under ATO although I personally want to see what SMA 3 does between King's X and Farringdon in the New Year. |
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Post by programmes1 on Oct 17, 2019 16:47:58 GMT
On the SB fast just north of Preston Road there has appeared a new signal, it is covered over so not working yet. Anyone know what it is for as I think it's a bit early for the new system to reach there or are they getting ready.
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Post by MoreToJack on Oct 17, 2019 16:59:31 GMT
It will be the boundary signal for CBTC. It was installed about a month or so ago. Masts are now in place up to around Moor Park.
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Post by ijmad on Oct 17, 2019 22:50:07 GMT
I see some scheduled engineering works around the SMA3 area in late Feb of 2020, which look suspiciously like some final testing running over the boundaries.
Specifically a closure from Monument to Stepney Green.
Is this when it'll be commissioned now, do we think?
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Post by jimbo on Oct 17, 2019 23:33:51 GMT
I see some scheduled engineering works around the SMA3 area in late Feb of 2020, which look suspiciously like some final testing running over the boundaries. Specifically a closure from Monument to Stepney Green. Is this when it'll be commissioned now, do we think? Rather close to the March timetables! Is it essential for those? |
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Post by Deleted on Oct 18, 2019 0:28:56 GMT
I see some scheduled engineering works around the SMA3 area in late Feb of 2020, which look suspiciously like some final testing running over the boundaries. Specifically a closure from Monument to Stepney Green. Is this when it'll be commissioned now, do we think? Correct |
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Post by programmes1 on Oct 18, 2019 7:57:51 GMT
It will be the boundary signal for CBTC. It was installed about a month or so ago. Masts are now in place up to around Moor Park. Jack, Thanks for this now have another question which I'm hoping you can clear up. As you say it's for the boundary when they reach there but I thought and I could well be wrong but don't the trains change over systems at the boundary? the reason I say this is as it's the fast line does that mean thr train would have to stop before changing over. Hope I have worded this correctly. |
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Post by Deleted on Oct 18, 2019 8:01:29 GMT
The train will stop opposite Preston Road and change from tripcock mode to a controlled mode
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Post by MoreToJack on Oct 18, 2019 8:38:51 GMT
It will be the boundary signal for CBTC. It was installed about a month or so ago. Masts are now in place up to around Moor Park. Jack, Thanks for this now have another question which I'm hoping you can clear up. As you say it's for the boundary when they reach there but I thought and I could well be wrong but don't the trains change over systems at the boundary? the reason I say this is as it's the fast line does that mean thr train would have to stop before changing over. Hope I have wored this correctly. DistrictSOM has replied but just to elaborate slightly, yes - on both the northbound and southbound fast lines trains will have to stop in order to change from tripcock to ATO or vice versa. |
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Post by Chris M on Oct 18, 2019 8:41:33 GMT
What is the current plan for how long this location will be an active boundary? (i.e. how long between commissioning of this SMA and commissioning of the adjacent one?)
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Post by Deleted on Oct 18, 2019 8:50:48 GMT
As yet nothing past SMA5 has a planned date
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Post by programmes1 on Oct 18, 2019 9:27:26 GMT
Thanks again for clearing that up.
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Post by goldenarrow on Oct 18, 2019 10:32:52 GMT
For those that haven’t passed through the area in the past few months:  Taken from a train on the NB Local parallel to signal A651 (SB Fast). |
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Post by jimbo on Oct 18, 2019 19:04:39 GMT
What is the current plan for how long this location will be an active boundary? (i.e. how long between commissioning of this SMA and commissioning of the adjacent one?) The last programme date I saw was for that signal to be commissioned in July 2021, when Baker Street control centre closes. The next area is planned in October 2021, so a while yet! |
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Post by MoreToJack on Oct 18, 2019 20:48:40 GMT
But as already point out, everything beyond SMA5 is very much aspirational at this moment in time. I would expect those dates to change, given the fluidity of 4LM thus far.
As always, it’s not hugely helpful to wave hypothetical dates around when staff involved/affected by the programme (we have a few here...) are being more realistic.
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Post by Chris M on Oct 18, 2019 21:50:11 GMT
My question was more intended to find out how long the signal will be in use and trains stopping on the fast, rather than absolute dates.
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Post by Deleted on Oct 19, 2019 19:20:33 GMT
until the next SMA is commissioned
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Post by A60stock on Nov 1, 2019 20:13:34 GMT
Excuse my ignorance on the topic of ATO:
Whilst I look forward to the benefits of ATO on the metropolitan line, i have been wondering as to whether ATO was needed north of wembley park, let alone Harrow on the hill? Are frequencies north of harrow really insufficient? (I am a regular peak hour commuter from the northern met and even the busiest of hours don't seem to shout that ATO is needed!)
Wondering if TFL could have saved money by installing south of Wembley only!
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Post by londoner on Nov 1, 2019 20:37:21 GMT
Excuse my ignorance on the topic of ATO: Whilst I look forward to the benefits of ATO on the metropolitan line, i have been wondering as to whether ATO was needed north of wembley park, let alone Harrow on the hill? Are frequencies north of harrow really insufficient? (I am a regular peak hour commuter from the northern met and even the busiest of hours don't seem to shout that ATO is needed!) Wondering if TFL could have saved money by installing south of Wembley only! You need to be able to reverse the trains to maintain a high frequency of trains per hour in the central core. I don't think you could achieve that all at Wembley. |
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Post by Deleted on Nov 1, 2019 20:38:14 GMT
The signalling is life expired and well past its sell by date hence the replacement so why not put the same system in everywhere. Less equipment to fail.
Alot of faults north of Wembley Park are either point or cable related, granted the points wont get changed saying that most of them are now Surelocks but the cabling is in desperate need of change.
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Post by goldenarrow on Nov 1, 2019 20:54:15 GMT
Some of the signals going are of WW2 vintage. In fact there are several signals that have started to reveal their distinctive rust coloured black out paint. Examples include platform starter at Harrow-on-the-Hill P6 and NB Harrow North Jct.
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Post by Dstock7080 on Nov 1, 2019 21:24:56 GMT
In fact there are several signals that have started to reveal their distinctive rust coloured black out paint. Examples include platform starter at Harrow-on-the-Hill P6 and NB Harrow North Jct. The “rust colour” or red oxide is the undercoat for the top silver colour. Many of us remember a time when a dedicated band of men would go along the open sections of Line from one end to the other, undercoating then top coating in bright silver the; high pressure air-main, equipment boxes and signal posts. Some boxes were painted bright green too. Probably stopped being done in the mid-late 80s ? |
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Post by Deleted on Nov 2, 2019 11:51:30 GMT
Stopped after company plan
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Post by spsmiler on Nov 3, 2019 22:10:25 GMT
For those that haven’t passed through the area in the past few months: Taken from a train on the NB Local parallel to signal A651 (SB Fast). To me this is an astonishment - placing a signalling migration area (SMA) boundary that requires a train to come to a complete halt in the middle of a section of railway designed for higher speed non-stop running. When passengers realise whats happening they will seriously question the thinking of the decision makers. Even if it is only 'temporary', such things can end up becoming more permanent than initially planned. I really am *that* surprised / shocked to learn that this is happening. Surely Harrow OT Hill would have been a better location for the SMA? After all, nowadays all trains stop there - even the rush hour Cheshams. (spoken as someone who remembers A stock Chesham trains running non-stop from Finchley Road to Moor Park!) It only makes any sort of sense when one sees it as part of an ongoing process of downgrading of the former Metropolitan Railway's main line service - including actions such as discontinuing services north of Amersham, reducing the scope of longer distance fast services (ie: call at more stations en route), closing the direct line from the main line to the Uxbridge branch at Harrow OT Hill platform 1, ending off-peak fast trains on the entire line, replacing higher speed points where the fast and local lines join (in the Watford area) with points designed for slower speeds, a new fleet of trains with lower top speeds and fewer seats.... even the all-day service to Chesham was only really done because it was 'operationally convenient' to have all trains the same length and this also meant that the bay platform at Chalfont & Latimer could be closed - instead of rebuilt. |
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Post by jimbo on Nov 4, 2019 3:18:40 GMT
For those that haven’t passed through the area in the past few months: Taken from a train on the NB Local parallel to signal A651 (SB Fast). To me this is an astonishment - placing a signalling migration area (SMA) boundary that requires a train to come to a complete halt in the middle of a section of railway designed for higher speed non-stop running. When passengers realise whats happening they will seriously question the thinking of the decision makers. Even if it is only 'temporary', such things can end up becoming more permanent than initially planned. I really am *that* surprised / shocked to learn that this is happening. Surely Harrow OT Hill would have been a better location for the SMA? After all, nowadays all trains stop there - even the rush hour Cheshams. (spoken as someone who remembers A stock Chesham trains running non-stop from Finchley Road to Moor Park!) It only makes any sort of sense when one sees it as part of an ongoing process of downgrading of the former Metropolitan Railway's main line service - including actions such as discontinuing services north of Amersham, reducing the scope of longer distance fast services (ie: call at more stations en route), closing the direct line from the main line to the Uxbridge branch at Harrow OT Hill platform 1, ending off-peak fast trains on the entire line, replacing higher speed points where the fast and local lines join (in the Watford area) with points designed for slower speeds, a new fleet of trains with lower top speeds and fewer seats.... even the all-day service to Chesham was only really done because it was 'operationally convenient' to have all trains the same length and this also meant that the bay platform at Chalfont & Latimer could be closed - instead of rebuilt. For simplicity, migration areas end at plain-line stations with automatic signalling. The size of area involved in each SMA is restricted by the time required for staff to bag old signals and peg old train-stops. There may also be a requirement to unbag new signals and test new train-stops in inter-operable areas, and to install new equipment that cannot be done earlier due to signal sighting problems, etc. All of this must also be reversed and tested at the end of each trial period. Complicated layouts at Wembley Park and Harrow/Hill rule these out as change stations, so a station between was chosen. By this time staff will be practised in the change-over routine at Finchley Road and Euston Square, so hopefully any stop on the fast lines will be brief. The following boundary will then become Moor Park, which will require all Mets to stop for change-over, but Chilterns can run through on colour light signals. |
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Post by goldenarrow on Nov 4, 2019 10:26:05 GMT
To be fair, I don't think there is a single suitable location for the MET Line that is ideal for the next migration boundary. Wembley Pk is too complex as is Harrow, West and North Harrow is fine for the Uxbridge branch and the Local line but the Fast lines would be pushed back to Moor Park. Before you know it you've swallowed up half the line. SMA 8's position also provides a clean break to close the last area of control from Baker Street.
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Post by uzairjubilee on Nov 5, 2019 8:38:17 GMT
Not sure if this should be in this thread or one in the District line thread, but is there an update on the use of platform 2 as a reversing point from the east at Tower Hill? I know that the paintwork is all in place, but a red signal at the east end of the platform is still in place?
Is this going to be changed after a particular timetable change?
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Post by goldenarrow on Nov 5, 2019 8:49:49 GMT
Not sure if this should be in this thread or one in the District line thread, but is there an update on the use of platform 2 as a reversing point from the east at Tower Hill? I know that the paintwork is all in place, but a red signal at the east end of the platform is still in place? Is this going to be changed after a particular timetable change? Its secured at the moment because it isn’t conventionally signalled up so will be brought into use with SMA 3 in the New Year. From then, trains will be able to reverse from/in that direction during disruption regardless of a timetable change which we are not due to have till 2020. The buffer stop that used to cap platform 2 is now at the overrun for the reception road at Uxbridge Sidings. |
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