Thought regarding emission standards

Discussion in 'Traction & Rolling Stock' started by jcollins, 7 Apr 2015.

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  1. jcollins

    jcollins Veteran Member

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    With coaches and larger lorries tighter emission standards have caused them to be limited to 62mph.

    However, with diesel trains we keep hearing you can't build one of those anymore due to tighter emission standards.

    Is it possible that limiting the top speed of a train could mean a train which just doesn't meet the latest emission standards could be a solution?
     
  2. jopsuk

    jopsuk Veteran Member

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    Are the speed limiters on large vehicles actually to do with emissions standards? And have manufacturers actually said that building DMUs is difficult due to emissions standards? Or is it a combination of misunderstanding, hearsay, over-simplification of the facts and (often) a desire to blame something on the dastardly EU?
     
  3. WatcherZero

    WatcherZero Established Member

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    Speed limiters nothing to do with emissions, its put on by the owners to stop them exceeding the speed limit (60 on Motorway) and having an accident which would leave them liable.
     
  4. jcollins

    jcollins Veteran Member

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    That's incorrect. Coaches and lorries under 7.5 tonnes maximum laden weight (unless articulated or towing a trailer) are permitted to do 70mph on the motorway: https://www.gov.uk/speed-limits but modern vehicles (not older ones) are limited to 100km/h (or 62mph) by a speed limiter so can't do their permitted maximum speed when travelling on a motorway.

    Yes some small vans have a speed limiter stopping them from going over 70mph but that's a different scenario.
     
    Last edited: 7 Apr 2015
  5. Bletchleyite

    Bletchleyite Veteran Member

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    No, they haven't. The 62mph limiter (100km/h) is not for emissions reasons, it is for safety reasons, and has existed since long before emissions were being considered much of an issue. That it conflicts with UK speed limits is a legal inconsistency between UK and EU law on separate but related matters.
     
  6. hwl

    hwl Established Member

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    3 separate issues getting confused
    a) speed limiters fitted to larger commercial vehicles (which need tachographs anyway)

    b) operators of smaller commercial vehicles worried about the size of their diesel bill. In this case the operators also usually de-tune the engines to reduce emissions (cut their fuel bill. The knock on effect is that the vehicles can't be driven as aggressively so accidents and insurance claim may have gone down.) See BT case study of £3+m pa fuel savings:
    http://www.fleetnews.co.uk/news/2012/11/6/fuel-economy-and-environmental-boost-for-bt-fleet/45339/

    c) Neither has anything to do with engines meeting standards.
    From what I understand the main issue on the railways has been finding the the space in existing dmu car designs (circa 15 years old) for the new larger exhaust systems that are needed to meet requirements. (I think particle filters being the latest additional item to find space for)
     
    Last edited: 7 Apr 2015
  7. Emblematic

    Emblematic Member

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    Light vehicle emissions are typically measured on the whole vehicle, on a standardized test cycle, and measured in terms of g/km. All elements of the vehicle design, such as vehicle mass, aerodynamics and transmission, are included and can affect the results (as an example, the disappearance of the spare wheel as a standard-fit item in cars is a direct consequence of emissions regulations.) The rail vehicle emission standards, like heavy vehicle and non-road engines, are typically expressed in terms such as g/kWh. Only the engine and associated emissions control systems, such as exhaust filters, are tested, on a standardized cycle which can be static or variable depending on application and standard in question. Adjusting the engine power output is one of many parameters available to the engineers in meeting the standards - however vehicle speed is irrelevant.
    As for DMU design, all I believe has been said is that the existing designs are non compliant, and fitting a stage IIIB engine & emissions control system would not fit these existing designs. So a new design, with the under-floor elements repackaged to suit (possibly with some components relocated above floor level) is needed. It's certainly not impossible, but it could well be expensive if there isn't a significant production run to recoup the design costs. As well as the D78, the Northern ITT inclusion of 120 or more new vehicles should give us some indication of what the manufacturers can offer.
     
  8. jcollins

    jcollins Veteran Member

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    Looking at the relevant wording it seems it wrong to say it's just for a reduction in pollution but also wrong to say it's not related to that at all as it's specially mentioned alongside improving road safety.

    http://www.legislation.gov.uk/uksi/2004/2102/pdfs/uksi_20042102_en.pdf

    http://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX:31992L0024
     
  9. cjmillsnun

    cjmillsnun Established Member

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    Correct, and the limiter setting for large lorries is 56 MPH (90km/h) max.
    --- old post above --- --- new post below ---
    The main reason for the promotion of them in the UK (they were starting to be fitted prior to the EU mandate) was road safety. Prior to the limiters trucks could easily exceed 70 MPH and did.
     
  10. TheKnightWho

    TheKnightWho Established Member

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    It's a complete myth that it's impossible to build new diesel trains due to emissions standards. The class 800s will be brand new diesel trains, and the class 68s are still coming on-stream.
     
  11. themiller

    themiller Member

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    If I remember correctly, the limit of 56mph for HGVs was introduced to reduce congestion as it enabled them to be presented at the south end of the M! in an orderly queue. Some time later, road coaches had a limit of 62mph imposed. This also had the effect of creating a measure of order at the ends of motorways. A side effect of these measures was to save fuel by stopping drivers from going flat out along the motorways. The economical speed of an internal combustion engine is some way below the maximum speed (not sure if this is true for gas turbines though). This also applies to engines in rail use hence the outbreak of shutting down engines once trains are up to correct speed and driver advisory systems.
     
    Last edited: 7 Apr 2015
  12. edwin_m

    edwin_m Established Member

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    I think another factor is the difference between CO2 emissions and other emissions such as Nitrogen Oxides and Particulates.

    CO2 emissions correlate almost exactly with fuel consumption, which for a road vehicle typically reduces up to about 55mph and increases above that. CO2 contributes to greenhouse emissions but is odourless and non-toxic so has no local impact unless the concentration becomes huge, which isn't going to happen unless run in an unventilated space.

    However the Euro emissions standards relate to the other emissions which are directly harmful to people nearby. I don't believe these are directly related to speed and even if they are the testing standard probably doesn't pick up that subtlety.
     
  13. cjmillsnun

    cjmillsnun Established Member

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    The original speed limiters fitted to trucks were 60 MPH (the speed limit) and to coaches 70 MPH (the speed limit). Neither were compulsory but were being promoted for road safety.

    When the EU directive mentioned above was introduced, the limits were reduced to 56 MPH for trucks (90 km/h) and 62MPH (100 km/h) for coaches for the simple reason that the EU (or EC as it was then) works in metric. It was at that stage that fitment became compulsory.
     
  14. edwin_m

    edwin_m Established Member

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    The statement made in a RSSB report was words to the effect that IIIB emissions standards were likely to make it impossible to build new underfloor engine DMUs for the British market.

    The class 800 has a raised floor to accommodate the diesel engine and associated kit - which they wouldn't have done had it been possible to fit it under a standard height floor. This solution wouldn't be possible if the doors were at 1/3 and 2/3 spacing. The class 68 is a locomotive so has far more space available than an underfloor DMU.

    It is very likely that the 120 new vehicles for the Northern franchise will be DMUs or bi-modes with 1/3 and 2/3 door spacing. So these should indicate whether manufacturers have managed to fit the entire engine equipment below the floor. One option might be to fit the exhaust processing equipment into the "crumple zone" near the coach ends that can't be used for passenger space.
     
  15. 47802

    47802 Established Member

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    Well despite what the RSSB report says MTU seem to have a compliant engine around the 500hp which I expect is more likely for a regional DMU which I doubt would need a raised floor like the monster v12 in the 800.

    All this has been discussed before on various threads, more regurgitation of the same old comments.

    As for the Speed Limit, as already been commented the EU speed limits were introduced well before the latest EU emission regulations so I doubt it has much relevance, As the 800 can do 100mph on Diesel I'm sure a regional DMU or Bi-mode can be produced with a 75 or 90mph speed limit on Diesel.
     
    Last edited: 8 Apr 2015
  16. HSTEd

    HSTEd Established Member

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    If they can't fit ~485hp engines like the ones in the 172s below the floor they could always go to aluminium/carbon fibre bodies/interiors to reduce the weight of the vehicles so they can use smaller, lower powered engines.

    Also a 172 vehicle weighs ~42.2 tonnes but has ~485hp
    If it had a Class 156's power to weight ratio it would only need ~330hp.
     
    Last edited: 8 Apr 2015
  17. TheKnightWho

    TheKnightWho Established Member

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    That will raise the cost by quite a bit, though, as you're directly increasing the cost of each unit. Developing a better engine just costs more R&D, which will decrease on a per unit basis as you buy more units.
     
  18. HSTEd

    HSTEd Established Member

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    Diesel emissions improvements are really into lots of diminishing returns though.

    This emissions stuff is the same regulatory ratcheting that did in the nuclear industry.

    And I doubt there will be many units ordered with this special ultra-compact emissions gear before the standard changes again and requires yet more R&D.
     
  19. SpacePhoenix

    SpacePhoenix Established Member

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    Could some of the equipment for emissions control go above buffer-beam level without taking up too much space?
     
  20. edwin_m

    edwin_m Established Member

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    MTU may well have an engine, it would be pretty surprising if they didn't, but the question is will it and the associated post-treatment equipment fit under a train?
     
  21. 47802

    47802 Established Member

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    Well if they can get it under the floor for an IEP 940hp engine I would think they coud manage it for a 500hp engine, and as far as the slope in the floor goes my understanding of that is to accommodate the monster v12 engine rather than associated equipment, and if there is a need to build DMU or Diesel Bi-modes better to build them now, than in say 6 years times when the I think the next set of emission regulations come into force.
     
    Last edited: 8 Apr 2015
  22. notadriver

    notadriver Established Member

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    I've often been asked by my coach driver colleagues why trains are allowed to go faster than 62 mph from a safety perspective. One won't travel by train because of this.
     
  23. jopsuk

    jopsuk Veteran Member

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    "because the railway is vastly more controlled environment, where there should never be the equivalent of small cars, motorbikes, bicycles, pedestrians etc and with a signalling system designed and operated to fully separate train movements with safety back up systems to reduce the possibility and impact of human error"
     
  24. DownSouth

    DownSouth Established Member

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    Correct.

    What is true is that it is difficult (but not impossible) to build Tier IV diesel-electric freight locomotives or multiple units for the toy train loading gauge used in Britain. It all comes down to the question of how much you're prepared to pay for the engineering work involved in the packaging, and what compromises you're willing to accept.

    The case you mention of the MTU gensets going under the floor of the Hitachi SET is an excellent example of this. To accommodate the new Tier IV compliant gensets and achieve the required performance, Hitachi were forced to build a humped floor where a version built for a market with less restrictive emission standards could have an older non-compliant genset underneath a flat floor.


    There are unlikely to be any new GE locomotives exported to Britain any time soon, as the Tier IV compliant GEVO package cannot fit - it's even too tall for Australian mainline* usage. I'm also not aware of them having confirmed that the PowerHaul engine has been certified as Tier IV compliant, GE would only take that step if it was both possible (it might be like the GE 7FDL engine and the EMD two stroke engines - impossible) and if there was a profitable market for it.

    Progress Rail Services (which absorbed EMD a few years ago) are also unlikely to be building a Tier IV compliant successor to the JT42CWR in the next few years as they do not yet have a full power (i.e. 3,300 kW) Tier IV loco for the domestic market in North America. The reality of business dictates that locos for export to the small UK/EU market will be a lesser priority than getting a full size loco ready for the much larger domestic market where they can sell many hundreds, even thousands if they do it right.

    Complicating this issue with the industry's big players is the problem that there is not as much chance in the near future for a widespread modernisation program similar to that which resulted in the JT42CWR orders being large enough that they had an economy of scale approaching that of a domestic model. Without the opportunity to sell a good number of them, Progress Rail and GE are not likely to put in the R&D work to package a good powertrain into a UK-size body.

    The result of all this is that UK operators will be paying well over the odds for any new diesel-electric locomotives for the foreseeable future, because they'll be at the mercy of buying bespoke designs from low-volume companies such as Vossloh which will use off-the-shelf prime movers or gensets from third-party suppliers such as Caterpillar, MTU and Cummins. These designs will get the job done, but they will not have any of the benefits to be found in a Progress Rail or GE design where there is the opportunity for internal collaboration (such as the work which went into repackaging the SD40-2 for UK use and for large-scale production to spread out the R&D costs.



    * The Australian mainline loading gauge is larger than that of Britain, but still well short of full size. Bureaucracy has so far prevented the type approval of taller locos on the Parkes-Adelaide-Perth and Adelaide-Darwin corridors where they would still be lower than the double-stacked containers they haul! No such restriction applies to the isolated iron ore railways in the Pilbara region which are the world's heaviest freight railways.
     
  25. Hophead

    Hophead Member

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    How big are the "donkey" engines that are to be fitted to the EMUs (for emergency use)? Will the electric SETs also require a raised floor?
     
  26. Domh245

    Domh245 Established Member

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    The electric SETs are being built with a raised floor anyway because then they only need 2 bodyshell designs, one for driving cars, and one for intermediate cars. It keeps costs down and makes it a bit simpler for construction and maintenance, if they are largely the same
     
  27. 47802

    47802 Established Member

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    As far as I am aware they are the same as the Bi-modes except there is only 1 engine or possibly 2 on a 9 car not sure.

    So there's a fair chance that even the electric units will be able to move themselves to the nearest station in the event of a power failure which given the crap wiring on the East coast is no bad thing.
     
  28. TheKnightWho

    TheKnightWho Established Member

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    I know the 800s are being built with the ability to remove the engines and convert them into 801s. Will consistency in bodywork (and presumably other component) design make the reverse possible? For example, when cascaded in several years onto partially/unelectrified secondary routes, or for the installation of donkey engines if it turns out there are issues?
     
  29. HSTEd

    HSTEd Established Member

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    Except the wiring on the East Coast is perfectly fine.
    The number of trains delayed on the East Coast by wiring problems is not much greater than that on the West Coast.
     
  30. 47802

    47802 Established Member

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    As someone who spent 5 hours stuck on a 91 when it managed to pull the wires down I don't think I'm entirely convinced of that, and train with a Diesel engine to power the Aircon would have been very welcome, especially compared with the state of the art solution used at the time of opening the doors and getting staff and BTP to guard them. :lol:

    Have you some stats you can share to show that?
     
    Last edited: 9 Apr 2015
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