In article , CJG
writes
Its been reported Virgin trains are being delayed up to 1 hour because
of National Rails headless chicken approach to a bit of sunshine.

Do you *ever* accept that somebody might know what they're doing when it
comes to running the railway? Or do you just like ranting nonsense?

In this case we're talking about basic physics. When you heat metal, it
expands. When you heat rails, they get bigger. That expansion has to go
somewhere.

Now back in the days of jointed rails you could put gaps between the
rails for them to expand into, but even then eventually the gaps filled.
With modern welded rail (providing a much smoother ride) you can't have
gaps. So, you anchor the rails firmly and install them so that they will
be at the right length when the temperature is 25 degrees C. If it gets
colder, they contract but the anchors pull on them, so the contraction
puts the rail under tension. If it gets hotter, they expand but again
the anchors pull on them and the rail goes under compression. Note that
the hotter it is, the more compression they are under.

If the rail is severely compressed *and* receives a severe blow at the
wrong point, the clips holding it on the sleepers and in line might not
be able to take the full force without giving way. Now the rail comes
free of the clip and buckles. This is clearly dangerous. So one thing
that can be done is to reduce the chances of a severe-enough blow, and
one way to do this is to reduce the speed of trains (track forces
increase with speed), particularly in areas at greatest risk.

On the run from King's Cross to Huntingdon last night there was *one*
emergency speed restriction - at the curve where the Hatfield derailment
happened. The rest of the run was at the usual 100mph. We were, IIRC, 3
minutes late overall (not just this one ESR; there are other longer-term
TSRs in place). This morning we've run normally as far as Stevenage,
which is where we are now.

--
Clive D.W. Feather, writing for himself | Home:
Tel: +44 20 8371 1138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Written on my laptop; please observe the Reply-To address

"Clive D. W. Feather" wrote the
following in:

In article , CJG
writes
Its been reported Virgin trains are being delayed up to 1 hour
because of National Rails headless chicken approach to a bit of
sunshine.

Do you *ever* accept that somebody might know what they're doing
when it comes to running the railway? Or do you just like ranting
nonsense?

The latter.

--
message by Robin May, founder of International Boyism
"Would Inspector Sands please go to the Operations Room immediately."

Unofficially immune to hangovers.

On Tue, 5 Aug 2003 07:03:45 +0100 Clive D. W. Feather wrote:
}
} In this case we're talking about basic physics. When you heat metal, it
} expands. When you heat rails, they get bigger. That expansion has to go
} somewhere.
}
} Now back in the days of jointed rails you could put gaps between the
} rails for them to expand into, but even then eventually the gaps filled.
} With modern welded rail (providing a much smoother ride) you can't have
} gaps. So, you anchor the rails firmly and install them so that they will
} be at the right length when the temperature is 25 degrees C. If it gets
} colder, they contract but the anchors pull on them, so the contraction
} puts the rail under tension. If it gets hotter, they expand but again
} the anchors pull on them and the rail goes under compression. Note that
} the hotter it is, the more compression they are under.
}
} If the rail is severely compressed *and* receives a severe blow at the
} wrong point, the clips holding it on the sleepers and in line might not
} be able to take the full force without giving way. Now the rail comes
} free of the clip and buckles. This is clearly dangerous. So one thing
} that can be done is to reduce the chances of a severe-enough blow, and
} one way to do this is to reduce the speed of trains (track forces
} increase with speed), particularly in areas at greatest risk.

This morning's Radio 4 news had it that "trains normally running at 110
mph" would be restricted to 60 mph.

Will such speed restrictions really make a significant difference in the
likelyhood of an incident such as you describe or is it aimed at
reducing the damage in such an event?

Tangentially why should this happen now and not in past years? After
all it's far from being the first time we've had a remarkably hot spell.

Matthew
--
Il est important d'être un homme ou une femme en colère; le jour où nous
quitte la colère, ou le désir, c'est cuit. - Barbara

http://www.calmeilles.co.uk/

Matthew Malthouse wrote:
Tangentially why should this happen now and not in past
years? After
all it's far from being the first time we've had a
remarkably hot spell.

It has happened in past years, frequently. It is also a problem in other
countries, it's just that we don't get to here about it. I suspect also that
in other countries there is a more ready acceptance that natural events are
not always under man's control.

People have short memories and it is only "news" for as long as the media
wishes it to be.

Matthew Malthouse wrote the
following in:

On Tue, 5 Aug 2003 10:27:58 +0100 Cast_Iron wrote:
} Matthew Malthouse wrote:
} Tangentially why should this happen now and not in past
} years? After
} all it's far from being the first time we've had a
} remarkably hot spell.
}
} It has happened in past years, frequently. It is also a problem
in other } countries, it's just that we don't get to here about
it. I suspect also that } in other countries there is a more
ready acceptance that natural events are } not always under man's
control.

So it has happened. But not hit the news. What's so special
about this year then?

Are you asking what's so special about this year that means it's in the
news this year?

--
message by Robin May, founder of International Boyism
"Would Inspector Sands please go to the Operations Room immediately."

Unofficially immune to hangovers.

Matthew Malthouse wrote:
On Tue, 5 Aug 2003 10:27:58 +0100 Cast_Iron wrote:
} Matthew Malthouse wrote:
} Tangentially why should this happen now and not in past
} years? After
} all it's far from being the first time we've had a
} remarkably hot spell.
}
} It has happened in past years, frequently. It is also a
problem in other } countries, it's just that we don't get
to here about it. I suspect also that } in other countries
there is a more ready acceptance that natural events are }
not always under man's control.

So it has happened. But not hit the news. What's so
special about this
year then?

Any attempt to work out what the differences are between this year and
previous practice would be idle speculation on my part.

Matthew Malthouse writes
} It has happened in past years, frequently. It is also a problem in other
} countries, it's just that we don't get to here about it. I suspect also that
} in other countries there is a more ready acceptance that natural events are
} not always under man's control.

So it has happened. But not hit the news. What's so special about
this year then?

1. It's hotter. (Forecasters expect to have the highest ever recorded
UK temperatures this week.)

2. Rail safety stories (however trivial) make big news since Hatfield.

--
Dave

In message , Clive D. W. Feather
writes
Do you *ever* accept that somebody might know what they're doing when
it comes to running the railway? Or do you just like ranting nonsense?

Well apparently part of the problem is not enough gravel/stones. I can't
remember the exact details. Something to do with it helps with the
expansion of the metal. Anyway the reason there isn't enough stones
round the rail? Cost-cutting.
And also the rest of the world manages to run its public transport with
2inches of snow, storms, rain, sunshine bringing the whole
infrastructure to a halt. So you tell me what the rest of the world has
that Britain doesn't?
Maybe a modern approach with finance used to its full potential?
--
CJG

CJG writes
And also the rest of the world manages to run its public transport with
2inches of snow, storms, rain, sunshine bringing the whole
infrastructure to a halt

So you reckon that public transport elsewhere in the world *never* has
any weather-related problems whatsoever?

Or is this just another of your sweeping generalisation with no
supporting evidence?

--
Dave

Dave wrote:
CJG writes
And also the rest of the world manages to run its public transport
with 2inches of snow, storms, rain, sunshine bringing the whole
infrastructure to a halt

So you reckon that public transport elsewhere in the world *never* has
any weather-related problems whatsoever?

Or is this just another of your sweeping generalisation with no
supporting evidence?

I think he regards the Evening Standard or some such rag as "evidence".
--
Richard J.
(to e-mail me, swap uk and yon in address)