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About West London Tram
Paul Terry wrote:
In message , Paul Scott writes It is comparatively difficult for them to overtake one another, and impossible for them to take a diversionary route in the event of roadworks, accidents etc. Surely it is trams that are unable to divert around roadworks, accidents, etc. (other than with the aid of crossovers and reverse working on an adjacent track). But what normally happens is that dedicated tramways are built. In much of Croydon this is the case. The trams only run on the roads in the town centre. Much faster than a bus. At least some parts of Geneva it's the same too. -- Paul |
About West London Tram
"David Bradley" wrote...
OK then let's take on board what you are saying here and let you into a preview of a page that will shortly be put up on www.tfwl.org.uk. You are invited to make suggested changes to ensure that a middle ground stance is taken provided it is honest and accurate. Well, you've certainly put a lot of work into this. I've got to give you that, at least. In my case, the more I get to grips with the detail of the sheme the more I became concerned about the sense and sensability of building a tramway along the Uxbidge Road corridor. Therefore everything is slanted towards a trolleybus solution. I don't believe those are the only two options. For example, the streetmaps show some branch lines coming off the Paddington railway line in West London. The Greenford line is still in use, but the line to Ruislip might as well be closed down, and AIUI the Hayes (or was it West Drayton?) to Uxbridge line was closed and removed ages ago. (I'm sure the trainspotters here can give us the full details if we need them) Why not convert a couple of those into a tram scheme? Say the Greenford line (because we know there's a demand for travel in that corridor) and the old Hayes/Uxbridge line (because TfL apparently wants a transit going to Uxbridge). Add on-street running to join the two the northern ends together in a loop and to cover places where the Uxbridge route has been built over, but the bulk of the lines will remain off-road. This way, it'll be building on TfL's solid, practical experience of running a mostly off-road tram network in Croydon. The links to Crossrail at the southern ends will be more useful to central London commuters than TfL's pointless proposal for a Shepherd's Bush terminus. And the fact that it's mostly a new rapid-transit route will grab people's attention more than just adding overhead wires to existing bus routes. (And while we're at it, what about sending some Crossrail trains up the old line to Ruislip?) No. I'm not seriously proposing this scheme. Just showing that a couple of minutes thinking outside the box can produce other new ideas at least as viable as TfL's trams vs. your trolleybuses. Just because there are flaws in TfL's scheme, it doesn't automatically make trolleybuses the best of all possible options. Solving congestion may be a rather tall order. If anyone claims that any form of WLT scheme (tram, trolleybus or whatever) is going to 'solve congestion across West London', they are to quote (a polite version of) the phrase: 'talking through their hat'. I don't think anyone's trying 'to solve congestion across all of West London.' Just reducing it along one main road is a much more realistic target. What is needed is a whole package of measures which will improve both the actuality and perception of public transport in this area and thus reduce the use of cars as much as possible. We need to 'improve both the actuality and perception of public transport' in all areas. There's nothing special about West London. WLT as a tram scheme does not give any greater benefits along the Uxbridge Road than a trolleybus scheme would but costs very much more. Warning. Now you're starting to use vague weasel-words. *A* tram scheme may or may not be better than *a* trolleybus scheme. It depends on the details of the schemes. Also the very nature of the WLT tram scheme proposed is likely to worsen flows by buses which are not simply along the Uxbridge Road (by creating a greater requirement to change - which is universally unpopular and thus often causes modal shift the wrong way). The advantages of trolleybuses is that they are non-polluting on street. Ah, now, do you see what you did there? You were talking about an advantage of trolleybuses over TfL's tram scheme, then in the next paragraph you continued talking about "advantages of trolleybuses" but actually, you've changed to their advantage over diesel buses. It gives the misleading impression that trams ARE polluting on street. The ability to steer trolleybuses across (both) the carriageway(s) and the design of the vehicles means that they can be better integrated into the overall bus provision along the corridor. Better integrated than diesel buses? Really? Oh, wait, no. You've sneakily switched reference points without telling us again and now you're comparing trolley buses to trams once more. Naughty David. You should be ashamed of yourself. There is no need to curtail services as will be done in the proposed tram solution. Sadly, long routes will probaly be split and curtailed anyway. It always happens. The tram would just've been a convenient excuse, but they'll find some other reason to curtail them if they look hard enough. This will therefore be beneficial in the general area around the Uxbridge Road. The lesser capital costs will allow funding to be available to improve these services further (including possibly electrifying many of them into trolleybus routes). You're rather niave if you think that TfL will automatically ringfence the saved money purely for the general area around the Uxbridge Road. They'll probably either spend it across all of London, or just line their pockets with it. I wouldn't dare say which one it'll be. As the design of WLT as a tramway does not integrate bus stops with trams stops I would hope that whatever mode of WLT is chosen, it wouldn't integrate its stops with bus stops. Keeping them separate would help establish it in the public's imagination as something new and different. This will help stimulate their curiosity more than just the same old bus routes calling at the same old bus stops but with added overhead cables. and even a 25 metre double artic would describe the same swept path. There is no experience whatsoever of 40 metre trams in UK streets, so we have no knowledge of how they will fare even with their fixed path. How much experience of 25 metre double artic trolleybuses is there in UK streets? If experience matters for one, it should matter for both. Even in that rarest of all situations that the overhead were damaged, trolleybuses could still operate using auxiliary power Is there any technical reason why trams can't be designed with auxiliary power for emergencies? I know TfL's specific tram scheme doesn't, but you do seem to be making the falacy of assuming that just because one particular trolleybus scheme is better than one possible tram scheme, therefore it must also be better than all possible tram schemes and all other possible schemes as well. The MORI survey (the one where the one line 'support for the scheme' headline is usually quoted) does not indicate that 'everyone' is in favour of the scheme - very far from it. Well, it would be VERY suspicious if a survey said 100% of people supported anything. Conversely many of those who 'supported' the scheme stated themselves that they had only limited knowledge of it. As more of the precise details are released, it is likely that even more people will oppose the scheme and not because they are all NIMBY drivers of gas guzzling 4 X 4 cars as is often disingenuously argued by pro-tram supporters but because they can see that the tram is not the optimum mode for this particular corridor Yes, but you're making that falacy again. You're assuming that just beacuse TfL's tram is not the optimum mode and your trolleybus isn't TfL's tram, therefore your trolleybus must be the optimum mode. It doesn't work like that. The world isn't all black and white. There are middle grounds and other options, but you aren't even interested in exploring them because of your trolleybus fixation. It's make you mind up time. Make our minds up? We haven't even begun to discover all the options yet... |
About West London Tram
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About West London Tram
In article , David Bradley
writes In fact in Rome where a new trolleybus systen has been introduced, part of the route has no overhead wiring because of a desire to have a clutter free skyline in an area of particular historical importance. The booms can be disconnected and reconnected to the wires without the need for the driver [or crew] to leave the vehicle. Clearly this ability can also be used in the first point that you made. I don't see too much difficulty in flicking a switch to lower or raise the booms as required, thus enabling that fabled overtaking of service vehicles, The only places where I've seen this de-wiring and re-wiring arrangement, the re-wiring can only be done at specific locations - there's a sort of plastic M attached to the wires that guides the booms into place. This is fine for the sort of situation you describe in Rome, but it does *not* work for unplanned overtaking. -- Clive D.W. Feather | Home: Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org Fax: +44 870 051 9937 | Work: Please reply to the Reply-To address, which is: |
About West London Tram
In article , David Bradley
writes High speeds are not likely to be a problem along the Uxbridge Road (the proposed mean speed for the tramway is 13 M.P.H.!). Is this mean speed while running, mean speed calculated start-to-stop, or mean speed from end point to end point? There's a huge difference between these. For example, consider a route 10km long with 29 intermediate stops (that is, a stop every 333m), assume that the dwell time at stops is 30 seconds, and that trams can accelerate and brake at 2m/s^2. I'll use 5m/s (11.2mph) for ease of calculation: * End-to-end speed of 5m/s means end-to-end time of 2000 seconds (just under 35 minutes). * 870 seconds is spent stopped, so that's 1130 seconds of running time, or just under 38 seconds between stops. That's a start-to-stop speed of 8.85m/s (19.9mph). * This requires accelerating to 10m/s (22.5mph), running at that speed for 28 seconds, then decelerating again. So the end-to-end speed is only half the service speed. There is no experience whatsoever of 40 metre trams in UK streets, so we have no knowledge of how they will fare even with their fixed path. There is experience with coupled pairs in Manchester and even Blackpool. We also have hundreds of years of experience of rail transport which shows us that all the vehicles follow the same fixed path, whether the combination is 5 or 500m long. -- Clive D.W. Feather | Home: Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org Fax: +44 870 051 9937 | Work: Please reply to the Reply-To address, which is: |
About West London Tram
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About West London Tram
On Thu, 10 Nov 2005 10:02:33 +0000, "Clive D. W. Feather"
wrote: In article , David Bradley writes High speeds are not likely to be a problem along the Uxbridge Road (the proposed mean speed for the tramway is 13 M.P.H.!). Is this mean speed while running, mean speed calculated start-to-stop, or mean speed from end point to end point? There's a huge difference between these. For example, consider a route 10km long with 29 intermediate stops (that is, a stop every 333m), assume that the dwell time at stops is 30 seconds, and that trams can accelerate and brake at 2m/s^2. I'll use 5m/s (11.2mph) for ease of calculation: * End-to-end speed of 5m/s means end-to-end time of 2000 seconds (just under 35 minutes). * 870 seconds is spent stopped, so that's 1130 seconds of running time, or just under 38 seconds between stops. That's a start-to-stop speed of 8.85m/s (19.9mph). * This requires accelerating to 10m/s (22.5mph), running at that speed for 28 seconds, then decelerating again. So the end-to-end speed is only half the service speed. There is no experience whatsoever of 40 metre trams in UK streets, so we have no knowledge of how they will fare even with their fixed path. There is experience with coupled pairs in Manchester and even Blackpool. We also have hundreds of years of experience of rail transport which shows us that all the vehicles follow the same fixed path, whether the combination is 5 or 500m long. It is unfortunate that all this nit picking continues with statements that I make concerning the viablity of tramway services along the Uxbridge Road. Responses to inaccurate statements, such as made here, have to be challeged before they become folklore. I would really prefere to actively persue development of my web site www.tfwl.org.uk where true facts are given following the most detailed research, as far as time permits, in anything that is said there. So you don't like the statement that mean speed for the tramway is quoted as 13 MPH. Well various TfL reports give the overall jourrney time from Uxbridge to Shepherd's Bush (20 km.) of around an hour and the mean end to end speed (thus including stops) of 19 or 20 k.p.h. (depends on which report!). I have (slightly generously) approximated this to 13 m.p.h. Clearly the vehicles should be able to exceed this between stops but it is unlikely that they will exceed 30 m.p.h. ( 48 k.p.h.) in doing so and in many places they will going far slower. They will have no opportunity for 'high speed' running of 50 m.p.h. (80 k.p.h.) which Croydon Tramlink achieves on many sections. Manchester is essentially railway branches joined together with very limited street running in between and a small section at the end of the Eccles Line. Blackpool is not on-street either except for a part at the Fleetwood end. The point is that the Uxbridge Road is **ALL** street and of course as all the information reminds us, a very congested street at that. The issue is not that of the path of the tram. That is clearly defined by the rails, as stated, The question is how you can fit the 40 metre length in the street between junctions, tram stops, stationary traffic of one sort or another, traffic 'nipping in' etc. Even with the flexibility of path available (by steering) of a bus, 'bendies' on London routes often have to be guided very carefully to be able to be squeezed into the available road space and these are 18 metres long. The tram has to occupy 40 metres of carriageway at any time. I believe that to get a clear 40 metres along some of the more heavily congested sections of this road, may at many times prove difficult and the tram will be delayed not because other traffic has stopped, but because of its own size. A good analogy would be that of artic lorries which are often unable to proceed even when other traffic is moving because there simply is not enough carriageway into which they can fit. the tram will of course be over twice the length of any artic lorry. This sort of problem can be experienced daily (only to a lesser extent as the trams are shorter than 40 metres) in those cities with extensive street running of their trams and congested streets such as Turin for example. David Bradley |
About West London Tram
On Fri, 11 Nov 2005 07:42:41 +0000, David Bradley
wrote: On Thu, 10 Nov 2005 10:02:33 +0000, "Clive D. W. Feather" wrote: In article , David Bradley writes There is no experience whatsoever of 40 metre trams in UK streets, so we have no knowledge of how they will fare even with their fixed path. There is experience with coupled pairs in Manchester and even Blackpool. We also have hundreds of years of experience of rail transport which shows us that all the vehicles follow the same fixed path, whether the combination is 5 or 500m long. The issue is not that of the path of the tram. That is clearly defined by the rails, as stated, The question is how you can fit the 40 metre length in the street between junctions, tram stops, stationary traffic of one sort or another, traffic 'nipping in' etc. Even with the flexibility of path available (by steering) of a bus, 'bendies' on London routes often have to be guided very carefully to be able to be squeezed into the available road space and these are 18 metres long. The tram has to occupy 40 metres of carriageway at any time. I believe that to get a clear 40 metres along some of the more heavily congested sections of this road, may at many times prove difficult and the tram will be delayed not because other traffic has stopped, but because of its own size. A good analogy would be that of artic lorries which are often unable to proceed even when other traffic is moving because there simply is not enough carriageway into which they can fit. the tram will of course be over twice the length of any artic lorry. This sort of problem can be experienced daily (only to a lesser extent as the trams are shorter than 40 metres) in those cities with extensive street running of their trams and congested streets such as Turin for example. The U9 (I think) that runs between Duesseldorf and Duisburg has a considerable stretch of street running after it emerges from below ground and before it goes onto reserved track north of the Messe. When they run double units, it takes up almost all the road between certain pairs of traffic signals. If that coincides with a tram stop, it stops everything. -- Terry Harper Website Coordinator, The Omnibus Society http://www.omnibussoc.org |
About West London Tram
David Bradley wrote:
On 7 Nov 2005 07:23:36 -0800, wrote: David Bradley wrote: On Mon, 7 Nov 2005 11:12:17 -0000, wrote: Now maybe you just happen to like bendy-buses with overhead power lines for their own sake? But experience seems to show that simply sticking bendy buses onto already overcrowded roads doesn't reduce congestion. I don't see how they're going to fix that problem by just adding some ugly power lines to the bus. 40 metre long trains, TWICE the length of bendybuses, running along Uxbridge Road is really going to make a difference for the better or worse? Your call to explain that one away. Perhaps it is, but it doesn't alter the fact that you haven't answered the question. Well let's have a go then although I have never said anything about using bendy trolleybuses although it's fair to assume that is what will be used. Not much of a go, unfortunately - the question was about why a trolleybus would reduce traffic congestion more than a similarly-sized diesel bus. The question isn't about pollution, or environmental issues, or the appearance of overhead wiring. They are all subjects worthy of debate in their own right, but they aren't the question currently posed. So how about taking another shot at it? Now it's about time you made your position clear of which mode of transport you prefer and why. I'm undecided, and open-minded, and open to persuasion by sensible debate. |
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