Wrong kind of pressure
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 |
Wrong kind of pressure
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) |
Wrong kind of pressure
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 |
Wrong kind of pressure
"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? ;-)) |
Wrong kind of pressure
And what 'engines' would those be? ;-)) 'Virtual' engines or 'blame' engines, as in something else to blame.. |
Wrong kind of pressure
And what 'engines' would those be? ;-))
Exactly what I said to the Fleet Manager this morning, it seems he was the "Spokesman" in the news article and told the staff and the media 2 diffrent things -- To reply direct, remove NOSPAM and replace with railwaysonline For Railway Information, News & Photos check out the Award Winning Railways Online at http://www.railways-online.co.uk |
Wrong kind of pressure
Joe wrote:
And what 'engines' would those be? ;-)) Exactly what I said to the Fleet Manager this morning, it seems he was the "Spokesman" in the news article and told the staff and the media 2 diffrent things Perhaps you could ask him why c2c attempted to blame the problem on an unusually rapid air pressure increase. I've had a look at the Met Office data for Shoeburyness for the night in question (Sun/Mon 18/19 April), and the pressure rose from 982mb at 22:00* Sunday to 992mb at 11:00 Monday. The Met Office uses words to describe the change in pressure according to the size of rise or fall over 3 hours. The fastest rises in any 3-hour period were of 3mb (22:00-01:00, 05:00-08:00, 06:00-09:00). There is nothing unusual about that. It would take a rise of double that rate to qualify as a "very rapid" rise in Met Office parlance. * All times BST. -- Richard J. (to e-mail me, swap uk and yon in address) |
Wrong kind of pressure
"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 |
Wrong kind of pressure
"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 |
Wrong kind of pressure
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 |
Wrong kind of pressure
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. |
Wrong kind of pressure
"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 |
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