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Old December 26th 04, 08:56 PM posted to uk.transport.london
Michael Bell Michael Bell is offline
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First recorded activity at LondonBanter: Jul 2003
Posts: 130
Default Eurostars quieter than Mark IVs + Class 91s?

In article , Terry Harper
wrote:
"Michael Bell" wrote in message
...
In article , Richard J.
wrote:
Michael Bell wrote:

Standing at Hitchin station and wistfully watching the fast trains
going through, the wheel-on-rail noise of class 91 + Mark IV
coaches seemed much louder than the Eurostars. (Comparisons with
HSTs are difficult because of their noisy diesel engines - at full
chat as they pick up speed going North). This was just a casual
observation. Is this generally accepted? Are the reasons known?

It may be because Eurostars (Class 373) are articulated, with one bogie
shared between two carriages except at the ends of each unit. Thus at
any instant while one is passing you, there are fewer bogies in contact
with the rails within x metres of your position than with a rake of Mark
IVs.


I got the feeling that the difference was greater than could be accounted

for
by that factor - and is it true anyway that there are significantly fewer
bogies per length of train? The body sections of TGVs are noticeably

shorter
than British Mark IV coaches.

Being analytical, what might the reasons be?


You might like to read one of the articles in January's Modern Railways,
which comments on the differences between forces on the track from different
wheel profiles, etc. "Seeking Excellence" on page 57.


Yes, I got that copy for the articles about the CTRL and St Pancras
rebuilding, but I haven't the local knowledge to make much sense of it. The
article you refer to doesn't mention noise. Or is it implied by the
discussion on conicity? And anyway, what does conicity measure?


Michael

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