Here's the "story". However, at Southend the pressure rose 10 mb in 12 hrs
8pm to 8 am,
hardly an "extreme change". (Source - METARs).

"Paul C" wrote in message
...
Wrong Kind of Pressure Disrupts Trains

By Peter Woodman, Transport Correspondent, PA News


Rush-hour rail passengers were treated to a new excuse for broken
trains today - the wrong kind of atmospheric pressure.

A sharp rise in atmospheric pressure caused havoc with the fine
workings of Electrostar 357 trains used on the Essex Coast to London
services run by the c2c company.

Eight of the trains lost power, causing severe delays to journeys into
and out of London's Fenchurch Street station.

A c2c spokesman explained: "Oil pressure plays a very important part
in the running of the engines on these trains and this pressure is
determined by atmospheric pressure.

"The atmospheric pressure in the c2c train area this morning was more
than twice what it was yesterday and this led to an airlock which, in
turn, led to the falling down of the pantograph which collects power
from the overhead wires."

He went on: "We had been working with our engineers to introduce a
modification to avoid this kind of problem, but it has not been
installed yet."


--
Paul

Robin Mayes wrote:

"Paul C" wrote in message
...
A sharp rise in atmospheric pressure caused havoc with the fine
workings of Electrostar 357 trains used on the Essex Coast to
London services run by the c2c company.
[..]
"The atmospheric pressure in the c2c train area this morning was
more than twice what it was yesterday and this led to an airlock
which, in turn, led to the falling down of the pantograph which
collects power from the overhead wires."
[..]

Here's the "story". However, at Southend the pressure rose 10 mb in
12 hrs 8pm to 8 am, hardly an "extreme change". (Source - METARs).

Indeed; roughly a 1% increase rather than the 100% claimed by c2c.
--
Richard J.
(to e-mail me, swap uk and yon in address)

"Richard J." wrote in message
...
Robin Mayes wrote:

"Paul C" wrote in message
...
A sharp rise in atmospheric pressure caused havoc with the fine
workings of Electrostar 357 trains used on the Essex Coast to
London services run by the c2c company.
[..]
"The atmospheric pressure in the c2c train area this morning was
more than twice what it was yesterday and this led to an airlock
which, in turn, led to the falling down of the pantograph which
collects power from the overhead wires."
[..]

Here's the "story". However, at Southend the pressure rose 10 mb in
12 hrs 8pm to 8 am, hardly an "extreme change". (Source - METARs).

Indeed; roughly a 1% increase rather than the 100% claimed by c2c.

......and surely negligible compared with the pressure surge when a train
enters a tunnel at speed ?

Has anyone got to the bottom of this weird story? Apparently it was on
Channel 4 News last night, but I missed it.

Steve P
Acton Bridge, WCML

"Steve Pardoe" wrote in message
...
Has anyone got to the bottom of this weird story? Apparently it was on
Channel 4 News last night, but I missed it.

The report I heard was quite clear. The pressure monitoring device in the
oil overflow chamber measured a change in pressure, and assumed that the
rate of change meant that the device was faulty, and shut them down.

This was reported months ago, and a software fix has already been developed,
but is still awaiting safety approval (what a surprise).

In the meantime, a man bleeds off the excess pressure in the chamber to
allow the train to restart.

Richard

On Wed, 21 Apr 2004, Richard wrote:

"Steve Pardoe" wrote in message
...

Has anyone got to the bottom of this weird story? Apparently it was on
Channel 4 News last night, but I missed it.

The report I heard was quite clear. The pressure monitoring device in the
oil overflow chamber measured a change in pressure, and assumed that the
rate of change meant that the device was faulty, and shut them down.

This was reported months ago, and a software fix has already been developed,
but is still awaiting safety approval (what a surprise).

In the meantime, a man bleeds off the excess pressure in the chamber to
allow the train to restart.

A likely story.

Oil overflow chamber = AE-35 unit
Train = HAL

A machine ruse, i tells you!

HTH.

tom

--
NOW ALL ASS-KICKING UNTIL THE END

Richard wrote:

"Steve Pardoe" wrote in message
...
Has anyone got to the bottom of this weird story? Apparently it was on
Channel 4 News last night, but I missed it.

The report I heard was quite clear. The pressure monitoring device in the
oil overflow chamber measured a change in pressure, and assumed that the
rate of change meant that the device was faulty, and shut them down.

This was reported months ago, and a software fix has already been developed,
but is still awaiting safety approval (what a surprise).

In the meantime, a man bleeds off the excess pressure in the chamber to
allow the train to restart.

The Main Transformer is basically a large tank in which the core
and windings sit in oil for cooling and insulation. At the
highest point in the tank is a small chamber designed to collect
any gas present. Once a certain amount of gas has accumulated,
this is detected and the unit is locked out by the software.

This is essentially a simplified version of the traditional
Buchholz Relay fitted to pretty well all traction transformers in
service (use Google if you want to know more) and its purpose is
to detect the early signs of arcing in an attempt to limit
further damage. The collected gas can be analysed and will aid
diagnosis of the fault.

Unfortunately, the c2c units have been causing trips due to air
appearing in the chamber, unrelated to any transformer faults.
The cause is still unclear, but there is a strong correlation
with certain atmospheric conditions - maybe it is like taking the
top off a pop bottle.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

"Chris J Dixon" wrote in message
...
The Main Transformer is basically a large tank in which the core
and windings sit in oil for cooling and insulation. At the
highest point in the tank is a small chamber designed to collect
any gas present. Once a certain amount of gas has accumulated,
this is detected and the unit is locked out by the software.


snip

Pardon me for de-lurking like this, but here's an interesting link about
transformer oil gas analysis:

http://www.chem.agilent.com/cag/peak...ansformer.html

.... interesting if you are into chemistry, at any rate.

Steve

On Mon, 19 Apr 2004 22:08:39 +0100, "Robin Mayes"
wrote:

Here's the "story". However, at Southend the pressure rose 10 mb in 12 hrs
8pm to 8 am,
hardly an "extreme change". (Source - METARs).

"Paul C" wrote in message
...
Wrong Kind of Pressure Disrupts Trains

By Peter Woodman, Transport Correspondent, PA News


Rush-hour rail passengers were treated to a new excuse for broken
trains today - the wrong kind of atmospheric pressure.

A sharp rise in atmospheric pressure caused havoc with the fine
workings of Electrostar 357 trains used on the Essex Coast to London
services run by the c2c company.

Eight of the trains lost power, causing severe delays to journeys into
and out of London's Fenchurch Street station.

A c2c spokesman explained: "Oil pressure plays a very important part
in the running of the engines on these trains and this pressure is
determined by atmospheric pressure.

"The atmospheric pressure in the c2c train area this morning was more
than twice what it was yesterday and this led to an airlock which, in
turn, led to the falling down of the pantograph which collects power
from the overhead wires."

He went on: "We had been working with our engineers to introduce a
modification to avoid this kind of problem, but it has not been
installed yet."


--
Paul


About 30psi or 2bar?

Keith J Chesworth
www.unseenlondon.co.uk
www.blackpooltram.co.uk
www.happysnapper.com
www.boilerbill.com - main site
www.amerseyferry.co.uk

"Keith J Chesworth" wrote in message
s.com...

A c2c spokesman explained: "Oil pressure plays a very important part
in the running of the engines on these trains and this pressure is
determined by atmospheric pressure.

And what 'engines' would those be? ;-))

And what 'engines' would those be? ;-))

'Virtual' engines or 'blame' engines, as in something else to blame..