Do Class 80x units have a theoretical top speed of 140mph on electric power?

Discussion in 'Traction & Rolling Stock' started by supervc-10, 26 Mar 2020 at 20:05.

  1. supervc-10

    supervc-10 Member

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    Don't the 80x family have a theoretical top speed of 140mph on electric? Like the Javelins?

    Edit:
    This was split off a thread about the 769s, which have a different top speed on electric to on diesel. I know the 80x are running at 125mph on both diesel and electric, but I'm sure I remember something about them being designed for 140mph.
     
    Last edited: 26 Mar 2020 at 21:15
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  3. Speed43125

    Speed43125 Member

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    They current gearing is for 125 mph(or strictly speaking, 200 km/h, so around 124mph). A big reason they are so much faster at accelerating than IC 225 sets is because they are geared properly, rather than 91s which are geared for 140 mph running (and seemingly are able to sustain 155+ running with the current gearing too).
    The 80x is designed to be 140 ready, so a change in gearing and it should have no issues doing 140, if we eventually get around to signalling upgrades that permit that.
     
  4. AlexNL

    AlexNL Established Member

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    Network Rail has selected Siemens and Atkins as their partners for the roll-out of ETCS L2 along the East Coast Main Line. The first phase covers resignalling London Kings Cross to Stoke Summit. :)
     
  5. hexagon789

    hexagon789 Established Member

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    The 80x are capable of 140mph on electric, they were specced to be able to run at that speed and I believe originally 110 on diesel for the bi-modern types.
     
  6. class26

    class26 Member

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    But it will need more than ETCS to enable 140 mph. Level crossings must also go before speeds higher than 125 mph can be permitted.
    There some lengthy stretches on the southern part of the ECML without crossings where it might be worth going faster such as Tallington- Stoke. Others will know of more examples perhaps ?
     
  7. jimm

    jimm Established Member

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    In fact, the IEP technical specification says the following about maximum speeds of the trains.


    From Page 21 at https://assets.publishing.service.g...s/attachment_data/file/82840/tts-redacted.pdf
     
  8. 59CosG95

    59CosG95 Established Member

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    Tallington - Stoke is the most obvious candidate for 140mph in the first instance, as the track along that length has a complete lack of level crossings and is plain line on all 4 tracks. North of Doncaster, the 'Selby Diversion' (i.e. Temple Hirst Jn - Colton Jn) could be another contender, but as there's no ETCS announced for that section of route yet, it's more of an academic proposal.

    South of Peterborough, you'd probably have to vastly reduce the number of crossovers on the ECML to make 140mph worthwhile, and you'd have to iron out the remaining bottlenecks (Welwyn Viaduct & Tunnels; Huntingdon-Woodwalton; Holme Jn-Fletton Jn) in order to achieve any meaningful time savings without being at the expense of capacity. And that's before the myriad number of level crossings from Arlesey to Peterborough are closed...
     
  9. samuelmorris

    samuelmorris Established Member

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    I believe the actual maximum speed of the AT300 as a product is 240km/h so almost 150mph, but that may not apply to the 26m vehicle length variant. Certainly 140 is as much as they'd ever be likely to see in the UK, if they were ever upped from 124.
     
  10. Meerkat

    Meerkat Established Member

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    I still can’t believe that there are so many level crossings on the ECML! Especially as many are in rural/semi-rural areas
     
  11. MarlowDonkey

    MarlowDonkey Member

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    Level Crossings are still in evidence on the Berks & Hants, but that's limited to 110 mph because it isn't straight.

    There's none between Paddington and Reading, but are there any west of Reading on the lines to Bristol and Cardiff?
     
  12. 59CosG95

    59CosG95 Established Member

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    Steventon (Stocks Lane, The Causeway). 'Nuff said.

    There are a few between Bath & Bristol as well AIUI, but there's no point running 140mph along there!
     
  13. hexagon789

    hexagon789 Established Member

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  14. Mikey C

    Mikey C Established Member

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    Why are level crossings a no-no at 140mph, but perfectly ok at 125mph which is still incredibly fast when compared to other surface transport?
     
  15. quantinghome

    quantinghome Member

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    Because at some point the speed is so high that level crossings are deemed unsafe. Whatever speed is decided on, it would always be possible to ask your question. But that doesn't mean it's the wrong decision. Otherwise you could repeat the argument and end up with level crossings being permitted at 200mph.

    The other point is that higher speeds would mean longer stopping distances and the barriers having to come down earlier. Coupled with increasing train frequencies, the level crossing becomes functionally useless as it ends up closed most of the time.
     
  16. II

    II Member

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    How much of an obstacle would station platform safety be for 140mph running? If costly modifications were required, that in itself might well be enough to scupper any thoughts of running at 140mph on the GWML.
     
  17. hexagon789

    hexagon789 Established Member

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    France runs TGVs at 220km/h (136.7mph) through open platforms on some lines and I think Germany might run ICEs at 230 (142.9mph) through some stations sans barriers.
     
  18. LNW-GW Joint

    LNW-GW Joint Veteran Member

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    And the Pendolinos in tilt mode.
    Also limited to 125mph by signalling constraints.
    They were procured for a 140mph tilting WCML which never materialised.
     
  19. II

    II Member

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    Thanks, I'm just wondering whether those platforms are purpose built for high speed running (i.e. nice and wide)? Somewhere with fairly narrow, or very busy, platforms Slough and Maidenhead or somewhere like Goring & Streatley are examples that might be different?
     
  20. hexagon789

    hexagon789 Established Member

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    And InterCity 225, which are marked for 140 on the data panels. I'm not sure if 80x are marked first 125 or 140 on the data panels though, I haven't managed to find a photo as yet
     
  21. hexagon789

    hexagon789 Established Member

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    The approaches to Paris Est off the LGV Est starts out with a 220 limit when the LGV joins the classic line and then progressively reduces speed. Though it seems the fast lines (220km/h) are not given platforms at the likes of Vaires-Torcy.

    Perhaps something on the classic line to Boreaux? That used to have some 210/220 sections for TGVs.
     
  22. Mikey C

    Mikey C Established Member

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    It just seems that allowing 125mph running was a compromise/pragmatic decision rather than one based on hard facts

    Is someone had decided that 100mph was the safe limit, then effectively most of our inter city network would be reduced to 100mph as the cost of replacing all the level crossings would be horrendous, and the disruption caused by closing them unacceptable.
     
  23. ac6000cw

    ac6000cw Established Member

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    I assume it's basically grandfather rights - regular 125 mph running started nearly 45 years ago with the first GW mainline HST services in 1976.

    The point of the HST was that they could run at 125 mph on largely the existing infrastructure (as there wasn't the money to replace it all), so after careful consideration and testing it was deemed safe to run at 125 mph through most existing platforms, full-barrier crossings, tunnels and bridges, using existing colour light signalling and AWS protection (but they did originally have another driver in the cab).

    It was 125 mph operation achieved on a relative shoestring in a different world back then (and a much less busy railway than today), but without it BR's InterCity services would likely have continued their downward spiral of decline.
     
    Last edited: 27 Mar 2020 at 13:42
  24. swt_passenger

    swt_passenger Veteran Member

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    Station platforms are covered by existing standards, they’re ok being passed at 140 mph, but with the restriction that above 125 mph no one can be allowed on the platform.
     
  25. II

    II Member

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    Thanks. I wonder if that restriction effectively means no likelihood of 140mph on the GWML then? With the possible exception of some sections between Didcot Parkway and Bristol Parkway/Chippenham which might not be enough to worth bothering about.
     
  26. hexagon789

    hexagon789 Established Member

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    Either the limit remains at 125 through stations or some means of closing off the platforms? Perhaps then 140 could be allowed.
     
  27. swt_passenger

    swt_passenger Veteran Member

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    I suspect the minor stations such as those between Reading and Didcot that presently have a fairly “porous” safety fence would have to have it replaced with a far more secure version. But a station where most but not all fast trains call would be problematical if people couldn’t be cleared from a platform before the next through train was due. Can’t see a safe solution to that...
     
  28. hexagon789

    hexagon789 Established Member

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    Platform edge screens?
     
  29. swt_passenger

    swt_passenger Veteran Member

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    That’s about the only really safe solution, but then you have issues with differing length of trains, door positions, stopping accuracy etc etc...
     
  30. II

    II Member

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    As well as cost...

    I guess if you somehow modified Didcot Parkway and closed off the main line platforms at Tilehurst, Goring and Cholsey unless a train was calling (staff to open up as and when necessary?) that would give you a clear run from Reading to Swindon (level crossings aside) which along with sections the other side of Swindon might just about be worth it? As long as no more stations are built, except for Grove which could be built on the up and down relief lines. The formation will also need to be up to it - there are some curves you can certainly feel at 125mph in the Pangbourne area.

    I can see it being more hassle and cost to much to be worth it though.
     
  31. AlexNL

    AlexNL Established Member

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    There are vertical platform screens, which look more like a sort of net. These could be installed along the length of a platform and will be able to accommodate any kind of train. Here's a video of a trial setup in South Korea:

     

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