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5 Eurostar trains fail due to condesation in the electrics

Discussion in 'Electronic Design' started by Raveninghorde, Dec 20, 2009.

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  1. http://news.bbc.co.uk/1/hi/uk/8422978.stm

    "Five Eurostar trains broke down in the Channel Tunnel on Friday
    night, after the move from cold air outside into the warmer tunnel
    caused condensation which affected electrical systems."

    Listening to a Eurostar spoken this morning he said there hadn't been
    weather like this for 8 years.

    1 failure is a breakdown, 5 at once is an engineering cock up.
     
  2. Sylvia Else

    Sylvia Else Guest

    It certainly seems that they can't tolerate rapid changes in
    temperature. Whether that's a cock-up, or an unfortunately unforseen
    circumstance remains to be seen, depending on the actual cause.

    Sylvia.
     
  3. No. Electrical and electronic systems designers have known about
    environmental issues for decades, and there is no excuse for having
    mission critical power switching gear going down for such a trivial cause
    and effect.
     

  4. As far as I am aware it has only happened to the Eurostar passanger
    trains. They were using car transporter trains to evacuate the failed
    Eurostars.

    For those who don't know the breakdowns happened in the channel tunnel
    between France and England closing the tunnel for hours.

    This led to cars being in 12+ hour traffic jams as the car transporter
    trains were disrupted. Made worse by UK border control staff in Calais
    being on strike causing massive disruption to the ferries ib the same
    area.

    So the motorway gets turned into a huge lorry and car park known as
    operation stack. I was listening to onw woman on the phone from her
    car who had moved a quarter of a mile in 13 hours, with a 3 year old
    in the back and no contact from the police or other services.

    http://news.bbc.co.uk/1/hi/uk/8423235.stm
     
  5. Those Tin whiskers are a bitch ;D

    Cheers
     
  6. It appears to me that by some accounts, the problem was the first
    snowstorm producing fine dry powdery snow blowing into the locomotives in
    a new way since 1994. That is only 25 years, and I have seen winter
    weather do nasty things in ways it does less often than that, such as
    blizzards in areas that only rarely get them, and really thick ice storms
    (as in 20-50 mm of rain falling while temperature is well below freezing).

    Since the longest period major oscillations in weather phenomena so far
    as I know appear to me to be the Atlantic Multidecadal Oscillation and a
    possibly-loosely-linked lower-frequency component of the Pacific Decadal
    Oscillation (both ballpark 60 year periods), I would look at weather for
    the past 70 years for problems that could occur again.

    Also, consider that the various atmospheric and oceanic phenomena whose
    last names are "oscillation" are at least generally not nice clean ones -
    but modulated in both amplitude and frequency by similar-frequency and
    lower-frequency random noise. Some of these "oscillations" may merely
    effectively be resonant bandpass filters (a few of them with Q rather
    low, maybe closer to 1 than to 2) acting on random noise of some sort.

    Heck, global temperature had a great single-year spike in 1998, due to
    an extreme El Nino. Only 1 of the 5 major global temperature indices goes
    far enough back to get a previous similar 1-year spike, and that one
    occurred in 1878 (by at least 1 account having an El Nino). These spikes
    are 120 years apart, roughly 2 periods of the AMO and of the lower
    frequency component of the PDO.

    It appears to me that one should look back through a stretch of time of
    more than 120 years, maybe 140 years, to see how the brown slop has some
    significant chance of hitting the fan.

    - Don Klipstein ()
     
  7. Talking about Ice storms, In around 1979 LI NY had a nice one 1/2" ice
    on every thing.
    Snapped wires, trees, Driving was impossible. Its been 30 years since.

    That 100 yr or 50 yr storm is still possible. The conditions have to be
    just right. Nothing has really change.

    Cheers
     
  8. PeterD

    PeterD Guest

    Heck with 30 years ago, New England had a massive ice storm last year.
    We are still repairing the damage (no help from the feds at all!) a
    year later.
     
  9. So they had their coldest snowstorm in 15 years. The most extreme
    winter precipitation event in any of several directions in 100 years in
    many locations stands out. Many locations in eastern USA have had only
    two blizzards since before 1888 - one in 1888 and one in 1993, both in the
    first half of March.

    - Don Klipstein ()
     
  10. Joerg

    Joerg Guest

    Which causes one to wonder why they didn't consult the guys up there, or
    at least the guys in northern Scandinavia. NIH phenomenon?
     
  11. Ken

    Ken Guest

  12. lurch

    lurch Guest


    Probably dumb and or ignorant periodic service and maintenance
    practices that left the cavity open to the elements.
     
  13. lurch

    lurch Guest

    The "safety critical area" has to be the train "machine" itself, not
    any place it traverses, EVERY place it traverses. It has to be the part
    that is failure proof (failure proofed/ruggedized).

    IIRC, the tunnel also has another emergency tunnel that passengers can
    exit the train and escape to from a smoke filled main tunnel.
     
  14. lurch

    lurch Guest

    Electrical power control "boxes" both internal and external, on such a
    device as a passenger train (or freight), should be sealed from the
    environment ALL of them. Gas and moisture tight, much less snow tight.
     
  15. Joerg

    Joerg Guest


    I meant places where a machine failure would cause panic and stuff. Just
    like an engine failure on a taxiing aircraft isn't a big deal but
    somewhere over the ocean it is. Been there, big 767 over the Atlantic,
    left engine went PHUT ...
     
  16. The problem is the lessons aren't learnt.
     
  17. Since the failures occurred deep inside the tunnel, it simply appears
    that the trains had been in the cold dry environment, possibly even
    powered down and the hardware temperature dropped lower than normally.

    Entering the warm and humid atmospheres of the tunnel, the hardware
    temperature was apparently below the dew point temperature of the air
    in the tunnel and water starts to condensate on any cold surfaces.
    This same happens when you spend some time in the cold and then enter
    a warm humid room and your glasses become opaque due to the
    condensation. Driving in extreme cold into a warm and humid road
    tunnel can cause dangerous situation, when there is a strong
    condensation on the windscreen or even freezing.

    Imagine what happens when condensation occurs on current PCBs with
    very small track to track distances. One way to avoid such problems is
    tropicalization e.g. by coating assembled and tested PCBs. Coating is
    often required in addition to the tropical climate also in polluted
    industrial sites and on ships, since the salty dust gets everywhere.

    I have no idea if Eurostar trains use tropicalized systems or not, but
    the failure mode seems to indicate that this has something to do with
    condensation and not just cold/hot/cold cycling.

    Problems like frozen pneumatic breaks are common when going from a
    relatively warm and humid environment to a very cold environment,
    which would cause condensation and ultimately freezing in the
    pneumatic lines, but this would occur only after an hour or two after
    _exiting_ the tunnel containing humid and warm air.
     
  18. lurch

    lurch Guest

    NOT inside ANY enclosure that was sealed with zero moisture inside, it
    doesn't.

    Ever heard of NEMA?
     
  19. It sounds to me like a good idea to have tested one of those locomotives
    there, or someplace that gets blizzards.

    It appears to me that blizzards do occur, even if only once every
    30 blue moons or whatever, in the USA as far south as Dallas and Memphis,
    and accumulating blowing dry snow short of a blizzard can occur as far
    south as Houston and Birmingham. I would hope that any transit vehicles
    made specifically for specific locations or areas can take whatever
    weather such locations get, including the weather they get rarely.

    - Don Klipstein ()
     
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