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Post by superteacher on Sept 3, 2007 21:35:21 GMT
Some people may be aware that by 2007, the Central line was to be fully upgraded so that in the peaks, 30tph will run in both directions betweem Leytonstone and White City. This was to be from 7am - 10am and from 4pm - 7pm. I recently wrote to TFL to enquire whether this was still the intention. The reply stated that this was the case, but was now not going to happen until 2011! Apparently, they need to upgrade the power supply before this level of service can be reliably operated. Am I alone in thinking that the supply had already been upgraded to handle a potential 33tph service? And the 2011 completion will mean that the Central line upgrade project will, by that time, have taken over 20 years to complete!
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Post by Deleted on Sept 3, 2007 23:06:40 GMT
It's a shame that stephenk is not around as much these days, as he could post a very exhaustive monologue explaining why anything higher than the current services are unlikely to run in the current operating climate.
The short answer is: dwell times on the Central Line are too high to increase the service any further without blocking back.
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mrfs42
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Post by mrfs42 on Sept 3, 2007 23:53:23 GMT
The short answer is: dwell times on the Central Line are too high to increase the service any further without blocking back. And the long answer about shortening the dwell times, identifying the headway limiters is.....  |
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Post by Deleted on Sept 4, 2007 1:12:40 GMT
The short answer is: dwell times on the Central Line are too high to increase the service any further without blocking back. And the long answer about shortening the dwell times, identifying the headway limiters is..... Beyond my meagre knowledge - what I know about it is gleaned mainly from the real experts like stephenk. |
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Post by Deleted on Sept 4, 2007 6:08:46 GMT
I suspect that there is not much that can be done about the dwell times. The car design is already pretty efficient in terms of providing adequate door space for the punters to get off and on.
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Post by Deleted on Sept 4, 2007 7:23:06 GMT
Did someone mention my name?
As far as I'm aware the Central Line cannot handle more tph than at present due to train availability. When the 92TS were ordered, there were more short reversers at stations such as White City, and Liverpool Street. Now the services have been extended for various reasons to reversing points further out. This combined with poor reliability (recently much improved!), and reduced top speeds (after Chancery Lane), have also decreased train availability. Signalling and dwell times should be able to support approx 33tph.
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Post by Deleted on Sept 4, 2007 17:51:43 GMT
Also, bear in mind that, less than 10 years ago, we had NINETEEN full 8-car trains laid up in 'long term store'... Only comparatively recently has the last one A-B unit, 91019, come back into service.
And to think the Upgrade project was bounced about as being called Central 2000.
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Post by superteacher on Sept 4, 2007 18:02:49 GMT
Interesting point about train availability and dwell times. It is true that train availability was an issue for the 92TS in the past, but they now consistently operate a 79 train peak service, so I don't think that's an issue any more. In respect of short reversers, this is only true during the off peak - the reason for extending the trains further out was to provide a 24tph off peak service from White City to Leytonstone. During the peaks, there were never any scheduled reversers at Liverpool Street, and the number reversing at White City is not too dissimilar to today, although some now run through to North Acton.
Back in the 70s, 30 tph was operated in both directions in the evening peak with a 75 train service, although the duration of this service was about 90 mins eastbound and 50 minutes westbound. So with higher performance trains, higher speed limits than in the past and more trains, it should easily be possible to increase the service beyond its current level.
Dwell times is an interesting one - these have improved since they decided to return staff to the platforms during the peaks with their "white lollipops"! The more frequent the service, the lower the dwell times due to there being fewer passengers exiting and boarding.
The letter I received from TFL, as I stated before, mentioned the power supply being the problem. Anyone "in the know" like to comment?
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Post by Deleted on Sept 4, 2007 18:09:20 GMT
Journey time, West Rui - Epping is now around 82 - 86 minutes.
SATS dispatch - moot point... when the platforms are packed, when looking at the in-cab monitors, you sometimes have to struggle to see the tennis bat...
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Post by Deleted on Sept 4, 2007 18:16:16 GMT
Journey time, West Rui - Epping is now around 82 - 86 minutes. In 62 stock days it was 89 minutes. I actually thought with ATO and faster 92s more time would have been shaved off. |
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Post by superteacher on Sept 4, 2007 18:18:53 GMT
Journey time, West Rui - Epping is now around 82 - 86 minutes. SATS dispatch - moot point... when the platforms are packed, when looking at the in-cab monitors, you sometimes have to struggle to see the tennis bat... Interesting point - high frequency peak services are great when there are no problems. When the eastbound peak service is running every 2 mins, the platforms never get desperately packed. Once there is a small delay, the platforms very quickly crowd uo, causing more delays, more crowding and so on! |
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Post by superteacher on Sept 4, 2007 18:24:24 GMT
Journey time, West Rui - Epping is now around 82 - 86 minutes. In 62 stock days it was 89 minutes. I actually thought with ATO and faster 92s more time would have been shaved off. I believe that the upgrade promised 10 - 15% off journey times, so that would mean a saving from 62 stock days of between 9 and 14 minutes. Remember that trains "wait time" at White City, Leytonstone and Loughton, which I think accounrs for 2 minutes of the journey time. In the current timetable, the quickest EPP - WER is booked to take 80 minutes. And as someone mentioned earlier, top speeds have been reduced since Chancery Lane, which affects long stretches of the Ruislip branch and the Epping branch east of Woodford. So I reckon that if the 92's were ever allowed to run at 100kph again, they could do the trip in 1 hour 15 minutes. Will they ever run at full speed again?? |
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Post by jamesb on Sept 4, 2007 18:28:15 GMT
How long are the 'tennis bats' supposed to be held up? Is it until the last carriage is clear of the platform? The bats seem good to say 'close the doors' but I've seen them held in all sorts of positions and very rarely held up until the train has left the platform. Journey time, West Rui - Epping is now around 82 - 86 minutes. SATS dispatch - moot point... when the platforms are packed, when looking at the in-cab monitors, you sometimes have to struggle to see the tennis bat... |
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Post by Deleted on Sept 4, 2007 18:34:47 GMT
When Central 2000 was bandied about, the suggestion was that the longest journey time would be 75 minutes...
Indeed I can remember when a 62ts journey took 96 minutes, so todays timings represents a saving of around 15 minutes, which isn't bad...
I would personally love to be able to run at 100kph again... EPP- Theydon would be a very lively ride, even with the new track!
Indeed Jim, with ATO, braking is left until the last possible moment, scary at times to see trains on full motor until they are halfway into the station! Yeah, more minutes could be clipped off the travel time... and an increase in frequencyt should be possible by clipping off turnround times at the outlying terminals... West Rui and Ealing Broodway..
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Post by c5 on Sept 4, 2007 18:37:36 GMT
How long are the 'tennis bats' supposed to be held up? Is it until the last carriage is clear of the platform? The bats seem good to say 'close the doors' but I've seen them held in all sorts of positions and very rarely held up until the train has left the platform. Journey time, West Rui - Epping is now around 82 - 86 minutes. SATS dispatch - moot point... when the platforms are packed, when looking at the in-cab monitors, you sometimes have to struggle to see the tennis bat... If my memory serves me correctly. It is until the first car is into the tunnel. This is for the "benefit" of lines with In-Cab CCTV OPO. On lines with OPO Monitors outside of the cab, it can be put down once the train has passed said monitors. Though the guidelines go with the former. |
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Post by Deleted on Sept 4, 2007 18:41:17 GMT
Until first car has left the platform... lot of the time the SATS staff leave them up for a great deal longer, at least half way out at times!
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Post by superteacher on Feb 1, 2018 13:05:50 GMT
Interesting to look back at this now (this thread contains my first ever post on DD  ), because it now seems that the Central line 1990's upgrade will never be fully completed as intended. OK, they now manage 34 tph for a 30 min period one way in the morning peak, but it looks like we will have to wait for the NEXT upgrade before we see anything like what was previously promised. |
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Post by stapler on Feb 1, 2018 14:54:12 GMT
Re Tubeoperator 92's post-- when will the line speed limit be raised again to 62mph? Will remotoring help?
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Post by superteacher on Feb 1, 2018 14:55:08 GMT
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), because it now seems that the Central line 1990's upgrade will never be fully completed as intended. OK, they now manage 34 tph for a 30 min period one way in the morning peak, but it looks like we will have to wait for the NEXT upgrade before we see anything like what was previously promised.
