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Which is cheaper: Diesel or Electric?

  • 10-08-2013 5:59pm
    #1
    traindude
    Closed Accounts Posts: 15 ✭


    To run a railway, is using diesel engines cheaper, since you don't have to have all those electrical wires and and such. I've always seen electrical systems as messy and complicated.


Comments

  • #2
    corktina
    Closed Accounts Posts: 17,733 ✭✭✭✭corktina


    i'd say electric is much cheaper once you have the infrastructure in place.


  • #3
    Cookie_Monster
    Registered Users Posts: 24,468 ✭✭✭✭Cookie_Monster


    will also depend how the electricity is generated. DART elec is coal / gas burn generation whereas as say the Swiss system is largely Hydo generated.


  • #4
    hfallada
    Closed Accounts Posts: 4,180 ✭✭✭hfallada


    I presume in places like France with the large amount of cheap nuclear energy electric is cheaper. But in America where Diesel isnt commonly used at all ( its one of the few petroleum products America export as there isnt a large demand for it) I imagine Diesel is cheaper.


  • #5
    dowlingm
    Registered Users Posts: 5,309 ✭✭✭dowlingm


    well "traindude" , look at New York's system - electric as far as the eye can see. Once you have to tunnel diesel starts getting inconvenient. Diesel above 125mph is usually impractical. Diesel engines which have to rev to produce peak torque are outperformed by electric ones which are often limited more by passenger comfort than acceleration ability so electric is especially good in suburban operations. Electric engines can be quieter, their duty lengths aren't bounded by refuelling intervals but rather other considerations and the carbon impact of this transportation can be 10s or 100s of km away rather than in a dense urban area.

    On the other hand, diesel trains can use fuels like biodiesel in certain climates. 3rd rail electric has limitations in respect of speed and is more of a danger to trespassers. Overhead lines create clearance issues in respect of structures or may interfere with large vehicles such as double-stack freight wagons - a problem in North America where many commuter systems run on what are as far as ownership is concerned freight railroads. And yes, there is a significant additional capital investment and maintenance hit.

    To summarise: it depends.


  • #6
    corktina
    Closed Accounts Posts: 17,733 ✭✭✭✭corktina


    Cookie_Monster wrote: »
    will also depend how the electricity is generated. DART elec is coal / gas burn generation whereas as say the Swiss system is largely Hydo generated.


    what do all those windmills and the shannon barrage do then?:D


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  • #7
    corktina
    Closed Accounts Posts: 17,733 ✭✭✭✭corktina


    hfallada wrote: »
    I presume in places like France with the large amount of cheap nuclear energy electric is cheaper. But in America where Diesel isnt commonly used at all ( its one of the few petroleum products America export as there isnt a large demand for it) I imagine Diesel is cheaper.

    I dunno about that, all those freight trains and huge convoys of trucks run on diesel afaik


  • #8
    _Kaiser_
    Registered Users Posts: 28,647 ✭✭✭✭_Kaiser_


    corktina wrote: »
    what do all those windmills and the shannon barrage do then?:D

    Isn't that all for export to the UK market?

    Says it could be worth €18bn to the economy though - I assume that's before the Troika takes their cut!


  • #9
    ted1
    Registered Users Posts: 23,231 ✭✭✭✭ted1


    Well diesel trains are effectively electric.

    So you need to look at the efficiency of the diesel generators. Generating locally eliminates line transmission losses and traffo losses, but your restricted in your fuel mix.

    With fuel mix in mind you have to look at the different technologies, is a CCGT plant more efficent than a diesel generator, is wind, oil, coal cheaper and more efficent probably

    So yes I reckon grid generated electricity is cheaper than diesel trains. Between peak hours 5-7 which is also rush hour than diesel may have the upper hand as this is when electricity is dearest


  • #10
    steamengine
    Closed Accounts Posts: 2,372 ✭✭✭steamengine


    For 2012 wind energy supplied 15% of total electricity used.


  • #11
    ted1
    Registered Users Posts: 23,231 ✭✭✭✭ted1


    steamengine wrote: »
    For 2012 wind energy supplied 15% of total electricity used.

    Wind isn't free and you need to look at the time of day, few trains run at night which is when wind blows. You need to look at the availability of wind during the operational hours of the rail fleet.


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  • #12
    steamengine
    Closed Accounts Posts: 2,372 ✭✭✭steamengine


    ted1 wrote: »
    Wind isn't free and you need to look at the time of day, few trains run at night which is when wind blows. You need to look at the availability of wind during the operational hours of the rail fleet.

    That 15% is an average figure for the whole of 2012, there are recorded peaks of 50% plus. That wind blows at night is indeed news to me ! In any event I'm not advocating anything. The way things are going the frackers will probably win out anyway - money talks.

    This link gives some idea of the savings using electric v. diesel in the UK, but the high capital cost of overhead electrification has to be recouped which is in turn dependent on high frequency operations which would not apply to Intercity services here, but could apply to suburban routes eg Maynooth, Drogheda in the future.


  • #13
    Cool Mo D
    Registered Users Posts: 1,419 ✭✭✭Cool Mo D


    The actual answer is that an electric train is generally cheaper to run than a diesel one, but the extra infrastructure for electric trains costs money to maintain. So electrification lowers costs on busy lines, but not on quiet ones.

    Electric motors also have better performance than diesel, so very hilly places with cheap electricity (like Switzerland) are almost all electric, even on quiet rural lines.


  • #14
    traindude
    Closed Accounts Posts: 15 ✭traindude


    wonderful answers, thank you all.

    Here is your reward: http://www.youtube.com/watch?v=R2G1T5HDTXM


  • #15
    dowlingm
    Registered Users Posts: 5,309 ✭✭✭dowlingm


    ted1 wrote: »
    Well diesel trains are effectively electric.
    Diesel locomotives maybe, but Irish Rail DMUs are diesel-hydraulic.


  • #16
    dowlingm
    Registered Users Posts: 5,309 ✭✭✭dowlingm


    corktina wrote: »
    I dunno about that, all those freight trains and huge convoys of trucks run on diesel afaik
    I think the point may have referred more to road diesel. Until recently North American diesel had far higher sulphur content than Euro diesel, which ruled out European diesel cars because their catalysts would be poisoned by the sulphur. It's only now that you're starting to see diesel pumps show up in standard retail petrol stations.


  • #17
    SeanW
    Registered Users Posts: 8,719 ✭✭✭SeanW


    dowlingm wrote: »
    well "traindude" , look at New York's system - electric as far as the eye can see. Once you have to tunnel diesel starts getting inconvenient.
    Actually not;

    Yes there are a lot of electric trains, but when DC powered 3rd rails are involved (as they are on the ex New York Central based Metro North Railroad, and the Long Island Railroad which was formerly associated with the Pennsylvania RR) you will find that the modern agencies prefer to run long distance trains with diesel as much as possible, such that Long Island RR diesel trains that run with "dual mode" locomotives, which once ran in e-mode as far out as Jamacia, now use diesel for everything except the Penn tunnels.

    As for Metro North the situation is even more bizarre: not only do long distance trains to Danbury, Wassaic and Poughkeepsie use diesel-only for everything outside Grand Central and the Park Avenue Tunnel, the drivers leave the diesel engines idling underground because of "gapping" problems with third rail in GCT.

    But the situation is different in Philadelphia and New Jersey, where AC powered overhead catenary is more widely available, including into (whats left of) New York Pennsylvania station. New Jersey has a heap of electrified lines going into both Penn and Hoboken. Philadelphia AFAIK also has an extensive regional rail system that is also "wired" with AC/overhead. That does seem to be more attractive than DC/3rd rail.


  • #18
    MGWR
    Closed Accounts Posts: 611 ✭✭✭MGWR


    SeanW wrote: »
    Actually not;

    Yes there are a lot of electric trains, but when DC powered 3rd rails are involved (as they are on the ex New York Central based Metro-North Railroad, and the Long Island Railroad which was formerly associated with the Pennsylvania RR) you will find that the modern agencies prefer to run long distance trains with diesel as much as possible, such that Long Island RR diesel trains that run with "dual mode" locomotives, which once ran in e-mode as far out as Jamacia, now use diesel for everything except the Penn tunnels.

    As for Metro-North the situation is even more bizarre: not only do long distance trains to Danbury, Wassaic and Poughkeepsie use diesel-only for everything outside Grand Central and the Park Avenue Tunnel, the drivers leave the diesel engines idling underground because of "gapping" problems with third rail in GCT.

    But the situation is different in Philadelphia and New Jersey, where AC powered overhead catenary is more widely available, including into (what's left of) New York Pennsylvania station. New Jersey has a heap of electrified lines going into both Penn and Hoboken. Philadelphia AFAIK also has an extensive regional rail system that is also "wired" with AC/overhead. That does seem to be more attractive than DC/3rd rail
    The dual-mode diesels have not been idling underground ever since the advent of the General Electric "Genesis II" P32AC-DM replacing the former New Haven FL-9s. The engines are not turned on through third rail gaps either; only in the case where a locomotive may be caught in a gap when stopped. The fastest that the dual modes can travel in electric mode is 60 mph, and since line speed on most former New York Central lines is 90 mph, the engine needs to be active during those periods; it is not a matter of preference, just of engineering limitations with third-rail dual mode engines. The prior operation of commuter rail on the Harlem and Hudson Lines involved an engine change to/from electric at outlying stations; it was the MTA that switched operations to dual mode. (The presently-disused overhead third rail in Grand Central was used to power these engines, as well as the New Haven Railroad's electrics when running in DC mode.)

    New York Penn's original electrification was all third rail with no overhead at all, save for overhead third rail to allow the DD-1 electric engines to be powered through gaps on the ground. The third rail on the New Jersey side originally went no further than the former Manhattan Transfer station in Harrison, New Jersey, where electric power was changed for steam. The AC overhead wires came at least two decades later, when the capital cost of extending third rail into New Jersey was found to be comparatively more expensive than the New Haven Railroad's system (which the Pennsylvania Railroad adopted); this also facilitated through-running with the New Haven when the Hell Gate line (aka New York Connecting Railroad) was built into Penn. Infrastructure costs for the AC overhead are far lower than with DC third rail (e.g. substations every ten miles versus every two, respectively); one trade-off is that in the case of tunnels, far higher vertical clearance is needed for the OHLE.

    The Long Island Railroad tried operating their DM30AC engines in electric mode at 80 mph, but the engines caught fire. Maximum speed in electric mode was slowed down to 60 mph and open-air operation of the diesel engines was instituted. Speed limit in the East River tunnels is 60 mph, for the record.


  • #19
    dowlingm
    Registered Users Posts: 5,309 ✭✭✭dowlingm


    New Jersey Transit has dual-mode/AC/overhead locos which are designed for 100mph in D and 125 in E mode. There were some issues about fire clearance for NY Penn so while some have visited I'm not sure if they are in full service (to that terminus) yet.


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