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Old October 11th, 2011, 11:51 PM   #4721
ill tonkso
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Ahhhhhh! Right
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Old October 19th, 2011, 03:12 PM   #4722
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I have a question about ATO lines, especially the Victoria. As I understand it, each train knows how far ahead the next train is and varies its speed accordingly. What I don’t understand is why the process can be so jerky. This is especially noticeable on the entrance to a station. If the train ahead has left the station, then by definition the path for the train arriving is clear – as it will stop at the end of the platform anyway. So why do trains often crawl into a platform, then accelerate for a few seconds, before stopping?

Thanks
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Old October 20th, 2011, 12:59 AM   #4723
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Quote:
Originally Posted by ChrisH View Post
I have a question about ATO lines, especially the Victoria. As I understand it, each train knows how far ahead the next train is and varies its speed accordingly. What I don’t understand is why the process can be so jerky. This is especially noticeable on the entrance to a station. If the train ahead has left the station, then by definition the path for the train arriving is clear – as it will stop at the end of the platform anyway. So why do trains often crawl into a platform, then accelerate for a few seconds, before stopping?

Thanks
The original Victoria Line ATO just gave the trains one of three commands: stop, go full speed (parallel), and go slowly (series), depending on on how close the train was to the train in front / the stopping mark of the next station.

If we have a train in a platform and another stationary train waiting a braking distance to the rear in the tunnel, then initially the train in the platform moves off and a few moments later the train behind does, initially in series as it's still close behind the train in front. As the train departing the platform leaves in parallel and down a gradient due to the 'hump' profile, it picks up speed rapidly, opening up the gap between the two trains (as the one behind is on an uphill gradient) to the point that the train behind then accelerates further into parallel. The system 'knows' how fast the train should be going at each point along the platform and so the train will accelerate to achieve this speed, doing so until it matches the maximum speed permissable at some point along the platform, the motors drop out, and the brakes apply.

So what you'll often see is a train leave a platform, the train behind crawl towards the platform, then accelerate fully along the platform, then start braking about halfway down.

This is needless acceleration and braking, but it does keep the distance between trains to an absolute minimum and speed up the service, however marginally. A manual driver will accelerate and brake less harshly if they've caught up the train in front, saving energy, but spreading the service out more and compounding late running.

Jubilee Line TBTC is a lot more 'intelligent' and does not appear to behave like this as noticeably. In fact, it's so 'intelligent' that normal line speed is a reasonable margin below what can be achieved, so that if a train is running to time it sticks to this somewhat impaired speed, but if it's running late, it'll belt along at full pelt until it catches up with its timetabled path. The timetable can effectively heal itself after a small-ish delay without any human intervention.
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Old October 20th, 2011, 02:28 AM   #4724
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Hi, I have some questions about the DLR:

1) Why the Tower Gateway station was built on a branch, and not on the line between Bank and Tower Hill so to give more trains and more direct services to both?

2) The past two days there weren't direct Stradtford International-Beckton trains, and the Stratford-Lewisham service was limited to Canary Wharf. Why?

3) When the latter goeas to Lewisham, does it use always the central platform at Canary Wharf?

4) Why West India Quays does exist, being attached to Canary Wharf, and why some Bank-Lewisham services stop there and others not? When these trains stop there? Maybe at off peak times, when the train use the flat junction instead of the flyover?

Thank you in advance!
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Old October 20th, 2011, 02:48 AM   #4725
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1)It was the original terminus, with the Bank branch coming later. A terminus there is still needed as Bank wouldn't be able to cope with turning all the trains without Tower Gateway taking some
2)Stratford Int-Beckton services only run 0530-0630, 1000-1600 and 1930-0030 - were you only looking at those times? (Stratford Int-Woolwich Arsenal trains only run at peak times - 0630-1000 and 1600-1930).
3)Stratford to Lewisham is every 12 minutes, morning peak-only, with all other services on that branch terminating at Canary Wharf
4)It's not attached to Canary Wharf, and (unlike Heron Quays nowadays) isn't that easy to get over the other side of the dock to Canary Wharf - from trains it's not blatant that there's water between the two stations on the ground. And yes, the flyover means that Docklands-bound trains using it (all of them before 1900) cannot stop at West India Quay.

http://www.tfl.gov.uk/gettingaround/1125.aspx <- here's a page with DLR service patterns and frequencies on it.
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Old October 20th, 2011, 05:23 PM   #4726
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Quote:
Originally Posted by Tubeman View Post
The original Victoria Line ATO just gave the trains one of three commands: stop, go full speed (parallel), and go slowly (series), depending on on how close the train was to the train in front / the stopping mark of the next station.

If we have a train in a platform and another stationary train waiting a braking distance to the rear in the tunnel, then initially the train in the platform moves off and a few moments later the train behind does, initially in series as it's still close behind the train in front. As the train departing the platform leaves in parallel and down a gradient due to the 'hump' profile, it picks up speed rapidly, opening up the gap between the two trains (as the one behind is on an uphill gradient) to the point that the train behind then accelerates further into parallel. The system 'knows' how fast the train should be going at each point along the platform and so the train will accelerate to achieve this speed, doing so until it matches the maximum speed permissable at some point along the platform, the motors drop out, and the brakes apply.

So what you'll often see is a train leave a platform, the train behind crawl towards the platform, then accelerate fully along the platform, then start braking about halfway down.

This is needless acceleration and braking, but it does keep the distance between trains to an absolute minimum and speed up the service, however marginally. A manual driver will accelerate and brake less harshly if they've caught up the train in front, saving energy, but spreading the service out more and compounding late running.

Jubilee Line TBTC is a lot more 'intelligent' and does not appear to behave like this as noticeably. In fact, it's so 'intelligent' that normal line speed is a reasonable margin below what can be achieved, so that if a train is running to time it sticks to this somewhat impaired speed, but if it's running late, it'll belt along at full pelt until it catches up with its timetabled path. The timetable can effectively heal itself after a small-ish delay without any human intervention.
Thanks, that makes sense – except that when the train in front has moved off from a station, shouldn’t it be considered parallel rather than series, ie. the train waiting in the tunnel behind accelerates hard straightaway?

I agree that the Jubilee seems to work better and be more intelligent, with trains knowing where several trains ahead are, as well as stations, so that they drive cleanly from one station to the next.
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Old October 21st, 2011, 12:01 AM   #4727
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Quote:
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Thanks, that makes sense – except that when the train in front has moved off from a station, shouldn’t it be considered parallel rather than series, ie. the train waiting in the tunnel behind accelerates hard straightaway?
I think there's also something around a train not being allowed to occupy any part of a platform until the train ahead has got a safe braking distance away from the station, combined with the fact that a train will not leave a platform until there is sufficient distance ahead for it to completely clear the platform before stopping again. This is to prevent a train departing then stopping half in half out, which creates the risk of people trying to board the rear cars, or equally stopping halfway down a platform as it enters, meaning people on the front cars pulling emergency alarms because they think the doors aren't opening.

Initially, as the train in the platform moves off, the train behind can creep up in series, but no further than the 'tailwall' (i.e. the start of the platform). It is only when the train in front has cleared the platform sufficiently that it has a safe braking distance between its rear and the platform headwall, that the train following it can wind up to parallel, as it is now allowed to occupy the platform. It will then motor in parallel until it reaches the maximum permissible speed at some point along the platform, and start braking.

If that makes any sense?!
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Old October 24th, 2011, 02:25 PM   #4728
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I think so. Thanks for the explanation!
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Old October 26th, 2011, 07:24 PM   #4729
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Will it be possible to extend the DLR Tower Gateway branch in the future? I realize it's an elevated terminus, but would it be possible to put it underground and continue into central london, perhaps to liverpool street (although that would duplicate the circle line from tower hill, metropolitan line from aldgate and h&c line from aldgate east, all within walking distance) or to kings x? or is it planned for the bank branch to be extended?
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Old October 26th, 2011, 10:38 PM   #4730
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Mysterious tube noises north of Kennington?

I live in an area just off Renfrew Road SE11, near Kennington Lane. There's an area of ex-council bungalows between some higher buildings - I live in one of the bungalows.

From time to time I can hear tube trains underground, and I know that the Charing Cross branch of the Northern line must run fairly close by. However, the sounds don't seem to be frequent enough to be caused by regular trains - I can go for several hours without hearing them (though one just went by as I wrote that).

A friend suggested that as a lot of trains do short turns at Kennington, perhaps there was an underground marshalling yard in my area - which could explain the single-floor houses. I know there's a loop at Kennington, but is there anything else under here that isn't obvious?

It gives a good excuse for quoting Annie Lennox songs, but... I'd just like to know
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Old October 26th, 2011, 11:14 PM   #4731
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I live in an area just off Renfrew Road SE11, near Kennington Lane. There's an area of ex-council bungalows between some higher buildings - I live in one of the bungalows.

From time to time I can hear tube trains underground, and I know that the Charing Cross branch of the Northern line must run fairly close by. However, the sounds don't seem to be frequent enough to be caused by regular trains - I can go for several hours without hearing them (though one just went by as I wrote that).

A friend suggested that as a lot of trains do short turns at Kennington, perhaps there was an underground marshalling yard in my area - which could explain the single-floor houses. I know there's a loop at Kennington, but is there anything else under here that isn't obvious?

It gives a good excuse for quoting Annie Lennox songs, but... I'd just like to know
You're right on top of the Charing Cross Branch there (Waterloo < > Kennington), so you should have frequent trains 19 hours a day... not too sure why it's so sporadic. Might just be a perception thing, if you're concentrating on other stuff you can easily tune things out... I grew up under the Heathrow flightpath and next to the District Line and only noticed the planes / trains when I had trouble sleeping and it was otherwise quiet.

There's no other Tube infrastructure nearby, so it's definitely the Charing Cross branch you can hear and nothing else.

Kennington Loop / siding are south of Kennington station.
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Old October 26th, 2011, 11:18 PM   #4732
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Will it be possible to extend the DLR Tower Gateway branch in the future? I realize it's an elevated terminus, but would it be possible to put it underground and continue into central london, perhaps to liverpool street (although that would duplicate the circle line from tower hill, metropolitan line from aldgate and h&c line from aldgate east, all within walking distance) or to kings x? or is it planned for the bank branch to be extended?
The Bank Branch effectively is an extension from Tower Gateway... or rather as close as they could get it. Tower Gateway itself will never be extended... the site is too constrained and there'd be too much prime property destruction.

The Bank branch remains the subject of extension talk, with one to the abandoned Jubilee platforms at Charing Cross being the most frequently suggested... I'm sure it will happen one day, just not sure when.
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Old October 28th, 2011, 04:08 PM   #4733
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An alternative might be building a new station just outside the tunnel of the Bank branch to replace Tower Gateway station. The problem is that it would be on a ramp and quite far from the existing station, the advantage that it would increase the service to both Tower and bank areas.
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Old October 28th, 2011, 06:17 PM   #4734
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I'm not sure if its the right topic, but I have a question... What is the fastest and best way from Waterloo to London St.Pancras station?
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Old October 28th, 2011, 06:30 PM   #4735
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Changing at Oxford Circus (from the Bakerloo line to the Victoria line) is the winner - not only is it (according to TfL) a minute quicker than changing at Leicester Square, but it is a very easy change.
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Old October 28th, 2011, 06:32 PM   #4736
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thank you very much!!!
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Old October 29th, 2011, 06:38 PM   #4737
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If you are planning to change between rail and underground at Waterloo and don't have any errand in Waterloo you might be able to change at Vauxhall instead of Waterloo. Then you have a direct connection to St. Pancras.

Similary if you don't have any errand at St. Pancras you might use Jubilee line to West Hampstead or Northern Line to Kentish town and change to rail there. Some St. Pancras trains call at Elephant and Castle, if that's the case for your train you might use Bakerloo line from Waterloo to Elephant and Castle.

Observe that only some trains call at Vauxhall, Kentish Town and West Hampstead. Check what apllies to your specific train. However all these suggestions has one less interchange than going from Waterloo to St. Pancras.
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Old October 30th, 2011, 12:06 PM   #4738
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If you are planning to change between rail and underground at Waterloo and don't have any errand in Waterloo you might be able to change at Vauxhall instead of Waterloo. Then you have a direct connection to St. Pancras.

Similary if you don't have any errand at St. Pancras you might use Jubilee line to West Hampstead or Northern Line to Kentish town and change to rail there. Some St. Pancras trains call at Elephant and Castle, if that's the case for your train you might use Bakerloo line from Waterloo to Elephant and Castle.

Observe that only some trains call at Vauxhall, Kentish Town and West Hampstead. Check what apllies to your specific train. However all these suggestions has one less interchange than going from Waterloo to St. Pancras.
Good call re: Vauxhall

Yes if the SWT service stops there, then change there. Most slower services do (e.g. Hampton Court, Hounslow Loop, Kingston Loop, etc).

But that is assuming you're changing to a SWT service... I guess you may just be arriving at St Pancras and staying in Waterloo?
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Old November 1st, 2011, 04:47 PM   #4739
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Tubeman - don't know if this is outside your wide area of expertise but do you have a view on how "season tickets" would be handled if TFL moved over completely to "Wave + Pay". Would it mean that each journey would be charged seperately or would it still be possible to buy a years worth of "all you can eat" travel?
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Old November 1st, 2011, 04:59 PM   #4740
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I can't speak for Tubeman, but surely any season tickets would still be available and loaded onto the card - and 'wave and pay' would just replace PAYG?
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