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Author: MIGMIG Date: Jun 27, 2008 06:31
I've noticed recently that the frighteningly wobbly stretch of DLR
from Mudchute to Crossharbour now seems to have a speed restriction,
although it still manages to wobble a surprising amount at very low
speed. I wonder if an opportunity will be taken during the works that
are about to start to fix whatever the problem is, or whether the
whole line will progressively be progressively reduced to a crawl.
Also, I wonder if this new speed restriction is due to the wobbling
actually having been unsafe, or was just to stop complaints from
alarmed passengers.
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Author: Neil WilliamsNeil Williams Date: Jun 27, 2008 09:11
On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
doreenbird.co.uk> wrote:
>Also, I wonder if this new speed restriction is due to the wobbling
>actually having been unsafe, or was just to stop complaints from
>alarmed passengers.
Have the DLR still not worked out how to deal with that issue? I
heard it was due to the use of tram-profile wheels on mainline-profile
rails. If that is the case, can't they just progressively replace or
reprofile the wheelsets?
Do the new sets have the same problem?
Neil
--
Neil Williams
Put my first name before the at to reply.
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Author: MIGMIG Date: Jun 27, 2008 09:22
> On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
>
> doreenbird.co.uk> wrote:>>Also, I wonder if this new speed restriction is due to the wobbling
>>actually having been unsafe, or was just to stop complaints from
>>alarmed passengers.
>
> Have the DLR still not worked out how to deal with that issue? I
> heard it was due to the use of tram-profile wheels on mainline-profile
> rails. If that is the case, can't they just progressively replace or
> reprofile the wheelsets?
>
> Do the new sets have the same problem?
I hope not, but I don't think any are in service yet. I haven't seen
any.
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Author: Paul CorfieldPaul Corfield Date: Jun 27, 2008 10:50
On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
doreenbird.co.uk> wrote:
>I've noticed recently that the frighteningly wobbly stretch of DLR
>from Mudchute to Crossharbour now seems to have a speed restriction,
>although it still manages to wobble a surprising amount at very low
>speed. I wonder if an opportunity will be taken during the works that
>are about to start to fix whatever the problem is, or whether the
>whole line will progressively be progressively reduced to a crawl.
>
>Also, I wonder if this new speed restriction is due to the wobbling
>actually having been unsafe, or was just to stop complaints from
>alarmed passengers.
Is it not to do with the fact that works are underway at Mudchute to
create a longer siding? It's fairly typical practice to reduce train
speeds near work sites.
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Author: MIGMIG Date: Jun 27, 2008 16:32
On Jun 27, 6:50 pm, Paul Corfield dsl.pipex.com> wrote:> On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
>
> doreenbird.co.uk> wrote:>>I've noticed recently that the frighteningly wobbly stretch of DLR
>>from Mudchute to Crossharbour now seems to have a speed restriction,
>>although it still manages to wobble a surprising amount at very low
>>speed. I wonder if an opportunity will be taken during the works that
>>are about to start to fix whatever the problem is, or whether the
>>whole line will progressively be progressively reduced to a crawl.
>
>>Also, I wonder if this new speed restriction is due to the wobbling
>>actually having been unsafe, or was just to stop complaints from
>>alarmed passengers.
>
> Is it not to do with the fact that works are underway...
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Author: thagor2008thagor2008 Date: Jun 29, 2008 15:16
> On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
>
> doreenbird.co.uk> wrote:>>Also, I wonder if this new speed restriction is due to the wobbling
>>actually having been unsafe, or was just to stop complaints from
>>alarmed passengers.
>
> Have the DLR still not worked out how to deal with that issue? I
> heard it was due to the use of tram-profile wheels on mainline-profile
> rails. If that is the case, can't they just progressively replace or
> reprofile the wheelsets?
I heard that but I'm not convinced. You don't get the wobble on pre-
metro systems on the continent nor the manchester metrolink. I'm
pretty sure its a train design fault that no one wants to admit to. A
decent suspension and bogie system should be able to cope with hunting
especially at the pretty low speeds the DLR runs at.
B2003
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Author: David CantrellDavid Cantrell Date: Jun 30, 2008 04:34
On Fri, Jun 27, 2008 at 04:11:58PM +0000, Neil Williams wrote:
> On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
> doreenbird.co.uk> wrote:>>Also, I wonder if this new speed restriction is due to the wobbling
>>actually having been unsafe, or was just to stop complaints from
>>alarmed passengers.
> Have the DLR still not worked out how to deal with that issue? I
> heard it was due to the use of tram-profile wheels on mainline-profile
> rails. If that is the case, can't they just progressively replace or
> reprofile the wheelsets?
Given that it doesn't happen elsewhere on the DLR (or not that I've
noticed anyway) then surely if that really is the problem then it's
that section of track that should be replaced, not the wheels.
--
David Cantrell | London Perl Mongers Deputy Chief Heretic
You can't judge a book by its cover, unless you're a religious nutcase
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Author: thagor2008thagor2008 Date: Jun 30, 2008 08:40
On 30 Jun, 12:34, David Cantrell cantrell.org.uk> wrote:> On Fri, Jun 27, 2008 at 04:11:58PM +0000, Neil Williams wrote:
>> On Fri, 27 Jun 2008 06:31:22 -0700 (PDT), MIG
>> doreenbird.co.uk> wrote:>>>Also, I wonder if this new speed restriction is due to the wobbling
>>>actually having been unsafe, or was just to stop complaints from
>>>alarmed passengers.
>> Have the DLR still not worked out how to deal with that issue? I
>> heard it was due to the use of tram-profile wheels on mainline-profile
>> rails. If that is the case, can't they just progressively replace or
>> reprofile the wheelsets?
>
> Given that it doesn't happen elsewhere on the DLR (or not that I've
> noticed anyway) then surely if that really is the problem then it's
> that section of track...
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Author: BRB Class 465BRB Class 465 Date: Jul 5, 2008 08:14
> Have the DLR still not worked out how to deal with that issue? I
> heard it was due to the use of tram-profile wheels on mainline-profile
> rails. If that is the case, can't they just progressively replace or
> reprofile the wheelsets?
It's not as simple as that. Wheelsets are a compromise between those
which perform well on straight track and those which perform well on
curves. On mainline railways this balance is easier to strike because
curves are normally not particularly tight. However the DLR has some
extremely sharp curves, for example at West India Quay, hence the need
for suitable wheelsets. Obviously this balance has not yet been
perfected, but it's by no means an easy thing to do.
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Author: Neil WilliamsNeil Williams Date: Jul 6, 2008 06:42
On Sat, 5 Jul 2008 08:14:43 -0700 (PDT), BRB Class 465
hotmail.com> wrote:
>It's not as simple as that. Wheelsets are a compromise between those
>which perform well on straight track and those which perform well on
>curves. On mainline railways this balance is easier to strike because
>curves are normally not particularly tight. However the DLR has some
>extremely sharp curves, for example at West India Quay, hence the need
>for suitable wheelsets. Obviously this balance has not yet been
>perfected, but it's by no means an easy thing to do.
Manchester Metrolink appears to manage it without such a ridiculously
poor ride, give or take on the sections of 50-year-old track.
Neil
--
Neil Williams
Put my first name before the at to reply.
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