Dual voltage Desiros and Electrostars

Discussion in 'Traction & Rolling Stock' started by Danielo, 22 Apr 2009.

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  1. Danielo

    Danielo Member

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    I was on a 'Southern' LM 350 yesterday from H&W to Shepherd's Bush. I times the voltage switch over at 25 seconds. It seems to be a lot quicker than the Electrostars. Is this the case?
     
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  3. jv3531

    jv3531 Member

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    Probably find its to do with the control system in use. The TMS has alot to do with how the trains handle things, some take longer than other and some have to be vertually reset before they can proceed.

    It could also be signal state playing a factor in the delay.
     
  4. 73110

    73110 Member

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    If an Electrostar is at Farringdon doing the changover from AC to DC, it can take up to 4 min's to do the changeover. Reason for this is if the unit is in the station by itself then it will be drawing too much current from the third rail, somehting like 800v+. Now if this happens the train doesn't like it and wont turn everything back on because of the high power coming in. The train won't let the voltage in if it's over 812v I think.

    Now, if there is a train in the other platform or directly in front of it then it will just take about a minute or so as the other train will be sharing the voltage in the station and the computer will let the lower voltage 'in' so to speak without fear of overloading.

    I have no idea though about the 350's.
     
  5. mackenzie_blu

    mackenzie_blu Member

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    I will admit the changeover on the 350's is quite quick and the CIS screen keep going unlike the Electrostars.

    As for the reasoning for the delay at Farringdon, whats the reason they have problems changing power when its an 8 car? I'll have to check how often the problem happens with 4 and 8 car mix.

    Thanks for the information about the voltage problems, quite interesting to hear that.
     
  6. jopsuk

    jopsuk Veteran Member

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    I'm right in thinking that Eurostar changed whilst on the move, yes? Presumably this didn't take several minutes?
     
  7. 73110

    73110 Member

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    For the same reason really. Too much power in the third rail. The current has to come below 800v I think or the thrain throws a wobbly.

    Don't know about that to be honest, only ever had one cab ride in a Eurostar and that was on DC hundreds of years ago!!! You can however do the changeover on a 319 on the move both ways if you really wanted to be daring!
     
  8. Danielo

    Danielo Member

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    You could be right there. I don't remember the Eurostar having to stop being entering the tunnel from the UK side before the days of HS1.
     
  9. A60K

    A60K Established Member

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    That's right - E* initially changed over east of Saltwood Tunnel, and later on the Gravesend West branch. In both cases changeover was on the move, normally at around 60-70mph.

    ISTR there was one occasion when the pantograph on a London-bound train didn't stow correctly leaving the CT, and a minute or two later it had an intimate encounter with the footbridge at Sandling :)
     
  10. Danielo

    Danielo Member

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    Is the Eurostar switch done instantaneously, or is there a short neutral section between the two voltages?
     
  11. 87015

    87015 Established Member

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    Used to be at least one "daring" Connex crew, was a bit of a shock the first time it happened!
     
  12. 73110

    73110 Member

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    I was at Farringdon years ago when a set of empties came though. Didn't stop at all. The pan just about went down before he went under the hook at the end of the wire. My mouth was wide open watching it go!!
     
  13. westcoaster

    westcoaster Established Member

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    hope it was a brecknell willis:lol: and not a stones faiverly(boy are they slow to go up and down):roll:
    --- old post above --- --- new post below ---
    was told there were also a few silverlink metro drivers, that would drop on the move in there 313's
     
    Last edited: 22 Apr 2009
  14. Pumbaa

    Pumbaa Established Member

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    Touch and go. Yes the CIS stays on, but one 350 I was on on the 14th of this month took around 90 secs to complete the proceedure.

    On the other hand, I like you have had a changeover in March at sub 20 seconds. The average, having had 4 return trips now, was to my mind around 30 secs. Still quicker than the average of 45 secs for Electrostar.
     
  15. O L Leigh

    O L Leigh Established Member

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    I've said this before on a number of ocassions, but it would appear it needs to be said again. You can drop a pan on the move but you can't raise one. If you do you risk damaging the pan and/or the OLE, and possibly even causing a dewirement. The ONLY exception to this is Eurostar which has a more sophisticated pan and better OLE.

    As for newer generation EMU's changing voltage, the time taken would be down to the TMS. I'm guessing that this interval would be the same as that when the unit goes through a neutral section, as the TMS needs a little breather whenever that happens. Any problems with voltage overload is likely to be sorted via a software update.

    As regards Farringdon, just why is the voltage there so high? Admittedly the 3rd rail can be anywhere between 650-750 volts so there is always likely to be a bit of variation, but 800+ volts sounds a bit much.

    O L Leigh
     
  16. 73110

    73110 Member

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    It is actual fact mate! On the MITRAC it shows you exactly how much voltage is coming in through each MCM and ACM. (Motor Converter Modules and Auxiliary Converter Modules)

    It takes mere seconds to shut off, go through the section and put the power back on again through a neutral section. On the 'Traction Status Screen on the MITRAC the MCM and ACM indicators go from green to yellow for a few seconds obviously whilst they have no power through the section.

    Whatever a "TMS" is it needs a bigger breather at Farringdon than it does at a neutral section.
     
  17. Pumbaa

    Pumbaa Established Member

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    Train Management System.
     
  18. O L Leigh

    O L Leigh Established Member

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    Sorry, I wasn't inferring that I didn't believe you. I was saying that 800+ volts sounds like a bit much for the trains. While I don't sign 3rd rail stock, I would imagine that might just be enough to trip out a unit's surge protection.

    Then clearly Electrostars are better than Desiros in this respect.

    The reason why I said this is that 25 seconds, which is the time delay quoted by the OP, sounds about the same amount of time as GE's Cl360's were offline after going through a neutral section. Through successive software upgrades this time has been reduced, but a Cl360 still doesn't come completely back to life for an appreciable period of time after going through a neutral, even after the VCB has closed again. It strikes me that this is, therefore, a TMS-related issue rather than a hardware problem. I'm guessing that certain systems go through a self-test routine whenever the power supply is restored after an interruption and that the TMS won't restore full power and control of all systems until they have all reported in that everything is still fine with them.

    O L Leigh
     
  19. 73110

    73110 Member

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    Ahh right. Strange things these trains eh!

    Bring back the old slam door stock, basic air and amps! :D
     
  20. O L Leigh

    O L Leigh Established Member

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    What do you mean "bring back"...? What do you think a Cl317 is...? ;)

    O L Leigh
     
  21. Danielo

    Danielo Member

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    Or just get the whole thing done by DMUs and do away with voltage switch overs
     
  22. asylumxl

    asylumxl Established Member

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    The 377s on the Thameslink route take ages to switch over compared to the 319s.

    Would be a good idea to add something to Farringdon to drop the voltage to eliminate delays?
     
  23. jopsuk

    jopsuk Veteran Member

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    Or wire up the Southern region.
     
  24. delt1c

    delt1c Member

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    The 317's were the 1st electric stock for the route. they were the electric class which started of the 3rd generation of EMU and are therfore probably over engineered and a lot more solid than the later designs.
    No slam door emus have worked the services.
     
  25. Daimler

    Daimler Established Member

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    Tell me about it! <( 6 mins at Farringdon on Thursday! Made the following train late!

    It's a good thing they aren't trying 24tph with 377s!
     
  26. asylumxl

    asylumxl Established Member

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    This morning, several Bedford trains were delayed by about 22 minutes. From what I saw traveling Southbound, they appeared to have been all 377s. Must have been stuck at Farringdon.
     
  27. mackenzie_blu

    mackenzie_blu Member

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    If Bombarbier get the Thameslink contract then we will be doing with Electrostar Mark 2!

    That was due to signalling problems at East Croydon delaying everything going through this morning. At it height offically 30mins delays were up on the boards. meaning it was likely higher.
     
    Last edited: 27 Apr 2009
  28. Edvid

    Edvid Member

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    I also understand that the 377 Ashford-Bedford service was affected by technical faults early on.
     
  29. asylumxl

    asylumxl Established Member

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    Yes. This is what i understood from announcements.

    Congrats on your 444th post btw lol.
     
  30. Edvid

    Edvid Member

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    Cheers :lol: :D
     
  31. Danielo

    Danielo Member

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    So, who wins? Electrostar or Desiro?
     
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