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Humps on tube lines
The Central London Railway began with Camel Backed Electric locomotives
hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. |
Humps on tube lines
Bob wrote:
The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. No but the effect of Metromess and TubeCrimes track replacements means that it feels as if you are going over speed humps at 50 mph, worst bit of track used it be Pic Acton to Hammersmith. |
Humps on tube lines
www.waspies.net wrote in
: Bob wrote: The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. No but the effect of Metromess and TubeCrimes track replacements means that it feels as if you are going over speed humps at 50 mph, worst bit of track used it be Pic Acton to Hammersmith. I didn't know that new lines were not built with a rising gradient on the approach to each station and a falling gradient on the departure from it. I'd have thought that the reasons for which the humps were originally built (helping slowing down on arrival, speeding up and reducing current consumption on departure) would be as valid today as they were 150 years ago. |
Humps on tube lines
"Bob" wrote in message oups.com... The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. Howson's book on the Underground [1981] describes the Victoria line as being built 'on a hump or sawtooth profile'; it is likely that the Jubilee line was built with the same falling and rising gradients. Paul |
Humps on tube lines
Is there anything approximating to a "200ft - Low - Club" on the London Underground? -- gordon |
Humps on tube lines
"www.waspies.net" wrote in message ... Bob wrote: The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. No but the effect of Metromess and TubeCrimes track replacements means that it feels as if you are going over speed humps at 50 mph, worst bit of track used it be Pic Acton to Hammersmith. Used to be being the operative words....I think the PPP mob replaced it didnt they...is it better now? |
Humps on tube lines
Martin Underwood wrote: www.waspies.net wrote in : Bob wrote: The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. No but the effect of Metromess and TubeCrimes track replacements means that it feels as if you are going over speed humps at 50 mph, worst bit of track used it be Pic Acton to Hammersmith. I didn't know that new lines were not built with a rising gradient on the approach to each station and a falling gradient on the departure from it. I'd have thought that the reasons for which the humps were originally built (helping slowing down on arrival, speeding up and reducing current consumption on departure) would be as valid today as they were 150 years ago. I think it was an innovation on the Central London Railway wasn't it, with the earliest lines not having it? None of them quite 150 years ago anyway. Maybe 105. |
Humps on tube lines
The Central London Railway began with Camel Backed Electric
locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street ... I think it was an innovation on the Central London Railway wasn't it, No. with the earliest lines not having it? The subsurface lines didn't do it; the cost of a cut-and-cover tunnel increases with depth. Tubes are another matter, and the first deep tube line, the City & South London Railway of 1890, did do it. (The part of this line still in use today is from Stockwell to near Borough on the Northern Line.) I don't have exact details on all the humps, but the book on the C&SLR by T.S. Lascelles says that "at most but not all stations there was a short down grade of about 1 in 30 to assist trains in accelerating", while Jackson and Croome in "Rails Through the Clay" say that "where possible, intermediate stations were built on humps". -- Mark Brader | "The job of an engineer is to build systems that Toronto | people can trust. By this criterion, there | exist few software engineers." --John Shore My text in this article is in the public domain. |
Humps on tube lines
Martin Underwood wrote: wrote in : Martin Underwood wrote: I didn't know that new lines were not built with a rising gradient on the approach to each station and a falling gradient on the departure from it. I'd have thought that the reasons for which the humps were originally built (helping slowing down on arrival, speeding up and reducing current consumption on departure) would be as valid today as they were 150 years ago. I think it was an innovation on the Central London Railway wasn't it, with the earliest lines not having it? None of them quite 150 years ago anyway. Maybe 105. Ah, so it's only a feature of the tube lines and not the cut-and-cover lines? I didn't know that. In that case, my approximate figure of 150 years (actually 143 years if you take the first Underground line as being built in 1863) changes to 105 years (Central line built in 1900), as you say. Apparently, from the other message, it was used on the C&SLR, which would make it 115 or so. |
Humps on tube lines
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Humps on tube lines
"Colin Rosenstiel" wrote in message ... In article , (Paul Scott) wrote: "Bob" wrote in message oups.com... The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. Howson's book on the Underground [1981] describes the Victoria line as being built 'on a hump or sawtooth profile'; it is likely that the Jubilee line was built with the same falling and rising gradients. Not everywhere, presumably because of other constraints. The approach to the King's Cross St Pancras Victoria Line platform from Highbury and Islington is downhill into the platform. Colin Rosenstiel I'm sure that is implied elsewhere in the text, and with the Victoria line at KX being the 4th or 5th pair of tunneled tracks I guess there would be many problems for the routeing of the tunnels past existing infrastructure. Paul |
Humps on tube lines
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Humps on tube lines
On Mon, 2 Jan 2006, Bob wrote:
Does anybody know if humps are still built into station tracks on new tube lines. The CTRL seems to do it: http://www.ctrl.co.uk/route/tile1.asp?L=8 Although i don't know if that's really about playing tricks with energy, or wanting to keep the tunnel nice and deep where possible. tom -- Chance? Or sinister scientific conspiracy? |
Humps on tube lines
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Humps on tube lines
Tom Anderson wrote: On Mon, 2 Jan 2006, Bob wrote: Does anybody know if humps are still built into station tracks on new tube lines. The CTRL seems to do it: http://www.ctrl.co.uk/route/tile1.asp?L=8 Although i don't know if that's really about playing tricks with energy, or wanting to keep the tunnel nice and deep where possible. When done by the CRL I don't think it was about "playing tricks with energy". Electricity was still a very new form of energy and such considerations hadn't arisen, it was simply a way of using a natural phenomenon (gravity) to improve the performance of the trains. However good the braking and acceleration of a vehicle on the level it will be enhanced by going up/down hill at the appropriate moment. |
Humps on tube lines
Tom Anderson wrote:
On Mon, 2 Jan 2006 wrote: Is there anything approximating to a "200ft - Low - Club" on the London Underground? Given that the only bit of the tube that's 200 feet down is the run between Golders Green and Hampstead [1], which takes all of a minute or two to traverse, i don't think such a pitiful display of stamina is something a gentleman would advertise! Doesn't mean that it hasn't been done though eh?! :-) |
Humps on tube lines
In message , Mal
writes No but the effect of Metromess and TubeCrimes track replacements means that it feels as if you are going over speed humps at 50 mph, worst bit of track used it be Pic Acton to Hammersmith. Used to be being the operative words....I think the PPP mob replaced it didnt they...is it better now? Not at all, they're still promising us that they will renew it all one day. We have a (permanent!?) 30 mph TSR to keep us going though, so that may be why things seem better. -- Steve Fitzgerald has now left the building. You will find him in London's Docklands, E16, UK (please use the reply to address for email) |
Humps on tube lines
"Tom Anderson" wrote in message h.li... On Mon, 2 Jan 2006 wrote: Is there anything approximating to a "200ft - Low - Club" on the London Underground? Given that the only bit of the tube that's 200 feet down is the run between Golders Green and Hampstead [1], which takes all of a minute or two to traverse, i don't think such a pitiful display of stamina is something a gentleman would advertise! tom [1] Cue corrections ... If you get out at the unfinished North End Station, you can stay there all night long. BTN |
Humps on tube lines
On Tue, 3 Jan 2006, Sir Benjamin Nunn wrote:
"Tom Anderson" wrote in message h.li... On Mon, 2 Jan 2006 wrote: Is there anything approximating to a "200ft - Low - Club" on the London Underground? Given that the only bit of the tube that's 200 feet down is the run between Golders Green and Hampstead [1], If you get out at the unfinished North End Station, you can stay there all night long. I believe North End's official name would have been Bull & Bush. Not clear which name offers the greatest innuendo potential, though. tom -- Plus, you gotta understand I can now type far, far faster than I can think. This is not boasting - its admitting a personal tragedy. -- D |
Humps on tube lines
On Tue, 3 Jan 2006, Brimstone wrote:
Tom Anderson wrote: On Mon, 2 Jan 2006, Bob wrote: Does anybody know if humps are still built into station tracks on new tube lines. The CTRL seems to do it: http://www.ctrl.co.uk/route/tile1.asp?L=8 Although i don't know if that's really about playing tricks with energy, or wanting to keep the tunnel nice and deep where possible. When done by the CRL I don't think it was about "playing tricks with energy". Electricity was still a very new form of energy and such considerations hadn't arisen, it was simply a way of using a natural phenomenon (gravity) to improve the performance of the trains. However good the braking and acceleration of a vehicle on the level it will be enhanced by going up/down hill at the appropriate moment. Er, that *is* playing tricks with energy - the uphill slope of the hump is a machine which converts the train's kinetic energy into gravitational potential energy, thereby assisting the brakes, and the downhill slope is a machine which does the inverse, delivering energy into the acceleration process, and so assisting the motor. It's exactly like using regenerative braking to turn a train's kinetic energy into electrical energy during braking, which can then be reconverted into kinetic energy during acceleration - only the hump does it rather more reliably and efficiently! A third equivalent would be a colossal spring lining the tunnel, which the train would compress during braking, and whose expansion would assist departure. Far less efficient (ISTR that you lose at least half the energy to heat when you do that), and probably not the most reliable or safe approach, either. tom -- Plus, you gotta understand I can now type far, far faster than I can think. This is not boasting - its admitting a personal tragedy. -- D |
Humps on tube lines
On Tue, 3 Jan 2006 20:51:55 +0000, Tom Anderson
wrote: On Tue, 3 Jan 2006, Sir Benjamin Nunn wrote: "Tom Anderson" wrote in message h.li... On Mon, 2 Jan 2006 wrote: Is there anything approximating to a "200ft - Low - Club" on the London Underground? Given that the only bit of the tube that's 200 feet down is the run between Golders Green and Hampstead [1], If you get out at the unfinished North End Station, you can stay there all night long. I believe North End's official name would have been Bull & Bush. Not clear which name offers the greatest innuendo potential, though. actually, it's the other way around. The station was to be called "North End," but over the years the abandonned works aquired the erroneous name of "Bull and Bush" amongst LU workers. -- Nick Cooper [Carefully remove the detonators from my e-mail address to reply!] The London Underground at War, and in Films & TV: http://www.nickcooper.org.uk/ |
Humps on tube lines
Tom Anderson wrote: On Tue, 3 Jan 2006, Brimstone wrote: Tom Anderson wrote: On Mon, 2 Jan 2006, Bob wrote: Does anybody know if humps are still built into station tracks on new tube lines. The CTRL seems to do it: http://www.ctrl.co.uk/route/tile1.asp?L=8 Although i don't know if that's really about playing tricks with energy, or wanting to keep the tunnel nice and deep where possible. When done by the CRL I don't think it was about "playing tricks with energy". Electricity was still a very new form of energy and such considerations hadn't arisen, it was simply a way of using a natural phenomenon (gravity) to improve the performance of the trains. However good the braking and acceleration of a vehicle on the level it will be enhanced by going up/down hill at the appropriate moment. Er, that *is* playing tricks with energy - the uphill slope of the hump is a machine which converts the train's kinetic energy into gravitational potential energy, thereby assisting the brakes, and the downhill slope is a machine which does the inverse, delivering energy into the acceleration process, and so assisting the motor. It's exactly like using regenerative braking to turn a train's kinetic energy into electrical energy during braking, which can then be reconverted into kinetic energy during acceleration - only the hump does it rather more reliably and efficiently! A third equivalent would be a colossal spring lining the tunnel, which the train would compress during braking, and whose expansion would assist departure. Far less efficient (ISTR that you lose at least half the energy to heat when you do that), and probably not the most reliable or safe approach, either. If you want to take "energy" in the widest sense, rather than the limited term meaning that which powers the train OK. |
Humps on tube lines
www.waspies.net wrote:
Bob wrote: The Central London Railway began with Camel Backed Electric locomotives hauling unpowered carriages. In order to improve efficiency distinct humps (mini summits) were built into the track profile at stations from Notting Hill to Liverpool Street - incoming trains were slowed by the rising gradient whilst outbound trains were hastened on their way by the falling out bound gradient. The heavy unsprung locomotives were soon replaced by multiple units with intermediate powered bogies. Does anybody know if humps are still built into station tracks on new tube lines. No but the effect of Metromess and TubeCrimes track replacements means that it feels as if you are going over speed humps at 50 mph, worst bit of track used it be Pic Acton to Hammersmith. Er, I actually think the track replacement programme is having an effect. Travelling around the network there are sections on many of the lines where there is a notably smoother and quieter ride, which I presume can only be the result of track repacement. It's still quite patchy - i.e. it may just be between certain stations, but at least the large scale programme has started. What comes to mind in particular is parts of the Northern line City branch, and parts of the Circle / District line (the southern shared section). Unsurprisingly they've both had weekend closures so track replacement work could be carried out on them. BTW I'm not cheerleading for MetroNet / Tube Lines here, as I understand they're behind schedule, and I suspect that despite the supposed private investment that the PPP's were supposed to bring to the table it's probably still public money that's paying for the bulk of this. It does appear to be happening though. |
Humps on tube lines
When done by the [CLR] I don't think it was about "playing tricks with
energy". Electricity was still a very new form of energy and such considerations hadn't arisen, it was simply a way of using a natural phenomenon (gravity) to improve the performance of the trains. ... As already pointed out, that amounts to the same thing. I'd just like to note that when the C&SLR decided to do it, they were expecting their trains to be cable-hauled, not electric. The energy and performance issues are of course essentially the same either way. But with cable haulage, a hump gives a special benefit. The train is accelerated from rest up to cable speed by tightening the grip until it clamps firmly onto the cable; and while that's going on, the cable is rubbing against the grip as it slides through it. So a gravity-assisted start could significantly reduce wear and tear on the cable. -- Mark Brader, Toronto | "If gravity stops working, a power cut is | the least of your problems." -- David Bell My text in this article is in the public domain. |
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