Porterbrook Cl.769 'Flex' trains from 319s, initially for Northern

Discussion in 'Traction & Rolling Stock' started by aformeruser, 2 Dec 2016.

  1. Llama

    Llama Member

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    What about when they also have a crush load of passengers in all vehicles? We had adhesion issues on the St Helens line in 2015 and a 319 couldn't move. The train crew ended up in desperation asking all the passengers to shift into the PMS vehicle for a bit more adhesive weight. (It didn't work).
     
  2. JN114

    JN114 Established Member

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    Well we might as well phone up Brush now then and tell them to stop converting 319s immediately. All the very highly paid engineers and designers in this project have clearly got their numbers wrong, as this one incident 4 years ago shows. Sprinters and Pacers have too failed to get away from stations when crush loading has coincided with exceptional railhead conditions; but we can carry on with running them because that doesn’t play to the perpetual 769 jeopardy narrative.
     
  3. Mordac

    Mordac Established Member

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    At least they didn't ask them to get out and push! :lol:
     
  4. AM9

    AM9 Established Member

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    I refer you to my earlier post in this thread, #2700 which shows the calculated loads and adhesive percentages of 319s and 769s when empty, all seats loaded and crush loaded*. Yes, the adhesive percentage goes down slightly with the additional genset kit on board the trailers but there are plenty of other multiple units with similar figures running around on services where they cope. Also forget this 'only 25% adhesive weight' argument. The MSOs weigh 50t whereas the trailers are all about 30t as EMUs so it is 50t powered vs 90t trailing. With diesel Gensets it is 50t powered vs 110t trailing. Those are figures for empty units. Read my other post.
    * 'crush loaded' is the rated capacity of the stock used for passenger flow calculations. 4 passengers per m^2 is perfectly normal in metro peak conditions,and whilst not the most comfortable way to travel, it is considered acceptable for short periods and exceptional circumstances.
     
  5. AM9

    AM9 Established Member

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    I assume that they will normally be driven from the same control in both modes and as 319s have always been, is that a four notch lever? If so, the 'notchieness' will be no worse and in some ways better as there will be less power available from the genset so wheelslip will be less likely. As far as hill climbing goes, they will be almost as capable on diesel as electric, (owing to slightly less adhesion) but the lower power will make progress slower. That power will though be more usable than with a mechanical or hydraulic transmission, because the genset will be running at maximum efficiency irrespective of wheel speed, and the motors will be running well within their ratings. That is a wholly different situatuation to the sprinter engine thrashing away into the torque converter which will converting much of the input power into heating its fluid and parts, resulting in less output torque.
     
    Last edited: 15 Mar 2019
  6. Greybeard33

    Greybeard33 Established Member

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    Can you back up this assertion with a curve of overall efficiency versus speed for the 319 traction system (traction motor plus traction converter), i.e. (mechanical power at railhead)/(750V electrical power in)? Plus a comparable curve for the 15x Voith hydraulic transmission, i.e. (mechanical power at railhead)/(shaft power in)?
     
  7. driver_m

    driver_m Established Member

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    I guess that would have been Thatto Heath/Eccleston Park which are notorious slide spots. Was told by one of my colleagues that he tried to stop a 142 there during the time of chain brakes, slid straight through, get the ok to set back and promptly slid back through too!!

    Even the best gripping units will struggle so I don't see how am argument what happened 'darn sarf' can be used for a train that hasn't even been used in service yet. Can't we all just see the 769 eventually work before passing judgement. We did the same with the 800's and they're neither as bad as people made out, nor the saviour of the railway, but somewhere inbetween.

    Let's wait everyone until they get a good run in the real world. .... .please?
     
  8. EE Andy b1

    EE Andy b1 Member

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    Well said that man!

    We can all speculate as much as we like but let's see these conversions in action.

    I don't think there is one traction or rolling stock or infrastructure program running on time or without further problems so lets just wait and see and hope they have come up with a descent product fit for purpose.
     
  9. AM9

    AM9 Established Member

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    So other than the reports of movements of donor or completed multiple units, there won't be much discussion. If that happens, those who seem to have some portents about any forthcoming rolling stock's dire failure will be nothing to say, and then they won't be able to shout 'I told you so' ad nauseum. :)
     
  10. FenMan

    FenMan Member

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    My local station is on the North Downs Line. I am totally agnostic about GWR's choice of rolling stock to run services as per the timetable. I can tolerate more or less comfortable seats, and, to a lesser extent, air cooling/heating not working as it should, etc, etc, if GWR uses rolling stock that does not extend the current journey times and is reliable.
     
  11. a_c_skinner

    a_c_skinner Member

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    Afraid so, but in truth until something happens that is all there is to say. I remain intrigued by the contrast between no main line testing yet apparently still deliveries going on and even (until recently) orders and people talking about orders. Mind you the 747 was ordered off the drawing board - though so was the 737 Max!
     
  12. Ken H

    Ken H Established Member

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    so is there a definitive table anywhere of the old 319 unit numbers and the new 769 numbers?

    looking at the table in wiki here - https://en.wikipedia.org/wiki/British_Rail_Class_769#Fleet_details - i see the 769 unit numbers are not contiguous. Does that mean they have retained the last 3 numbers of their 319 unit number? so 319424 becomes 769424?
     
    Last edited: 16 Mar 2019
  13. anamyd

    anamyd Established Member

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    yes!!!
     
    Last edited: 16 Mar 2019
  14. Ken H

    Ken H Established Member

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    fixed.
     
  15. anamyd

    anamyd Established Member

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    Example: Transport for Wales 769s are 769-002/003/006/007/008/(426)/4xx/4xx/4xx which are converted from 319-002/003/006/007/008/(426)/4xx/4xx/4xx :)
     
  16. td97

    td97 Member

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    Alderley-Wigan NW services are timed as class 319 EMU from May. Clearly must be some intention of the 769s starting this summer.
     
  17. Mathew S

    Mathew S Established Member

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    I'd missed that. Thanks
    Yes, that would seem a bit of a giveaway.
     
  18. Greybeard33

    Greybeard33 Established Member

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    Curiously, the services from Wigan NW or Southport to Alderley Edge are all timed for 75mph Sprinters. It is only (some of) the return services from Alderley Edge to Wigan NW/Southport that are timed for 100mph 319s!
     
  19. Siemens Staines

    Siemens Staines Member

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    I thought I read somewhere that the GWR 769s are only to retain the last two digits, e.g 319437 will become 769937, 769/9 indicating the retention of 750V capability. I don't recall where I saw that now, so perhaps I am wrong.
     
  20. anamyd

    anamyd Established Member

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    First I've heard of that but you could be right!
     
  21. Class 170101

    Class 170101 Established Member

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    There will be a change on route somewhere for the Traction type but Real Time Trains only shows the leading traction type I think you will find.
     
  22. geoffk

    geoffk Member

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    Also presumably WNW to Stalybridge as they interwork at Wigan.
     
  23. PHILIPE

    PHILIPE Established Member

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    Open Train Times will show any change of timing en route. Neither OTT or RTT shows the traction type
     
  24. Class 170101

    Class 170101 Established Member

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    RTT shows what it is pathed as. Clearly a Class 319 will not make it to Southport.
     
  25. PHILIPE

    PHILIPE Established Member

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    I know that.
     
  26. PHILIPE

    PHILIPE Established Member

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    I must apologise here for quoting OTT as showing any change of Timing Load. I should have said "BR Times" . Apologies again
     
  27. 59CosG95

    59CosG95 Established Member

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    I read the same thing too; it's to differentiate the fact that they are tri-mode units, rather than the bi-modal ones ordered for Northern and TfW.
     
  28. LOL The Irony

    LOL The Irony Established Member

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    They're not tri-modes! They're dual voltage bi-modes. Using the tri-mode logic porterbrook are using, every dual voltage EMU is a bi-mode.
     
  29. anamyd

    anamyd Established Member

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    Tri-modes have batteries, right...?
     
  30. Greybeard33

    Greybeard33 Established Member

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    Not the whole story. Liverail shows changes en route and traction type. From looking at a few examples, the Wigan NW to Alderley Edge workings have two changes en route, at Bolton and Manchester Piccadilly. For both the Wigan to Bolton and Piccadilly to Alderley legs, the data is:
    Code:
                  Power type: DMU Diesel Mechanical Multiple Unit
                 Timing Load: S Class 150, 153, 155, or 156
                       Speed: 075 mph
    
    Whereas for the Bolton to Piccadilly leg, the data is:
    Code:
                  Power type: EMU Electric Multiple Unit
                 Timing Load: 319
                       Speed: 100 mph
    
    See e.g. http://www.charlwoodhouse.co.uk/rail/liverail/train/15869059/18/07/19

    The Alderley to Wigan workings, on the other hand, have only one change en route, at Piccadilly. For both legs (including the unelectrified Bolton to Wigan line), the data is:
    Code:
                  Power type: EMU Electric Multiple Unit
                 Timing Load: 319
                       Speed: 100 mph
    
    See e.g. http://www.charlwoodhouse.co.uk/rail/liverail/train/15869807/18/07/19

    Make sense of that!

    No, the Wigan - Stalybridge workings are timed as Sprinters throughout, in both directions.
     
    Last edited: 17 Mar 2019

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