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Thread: Horsepower to Ton Ration Questions

  1. #1
    Join Date
    Nov 1999
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    Augusta, Ga, USA.
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    Default Horsepower to Ton Ration Questions

    First, what does it mean. Byt that I mean when it says 3:1, does that mean 3000 HP to 1 ton? And what are the formulas to determine this ration. Obviously, the ratio is much different on flat level routes as oppose to mountainous routes, so how do they figure the ration?

  2. #2
    Join Date
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    Eltham, Australia.
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    Default RE: Horsepower to Ton Ration Questions

    Hi Chris,

    3:1 means 3hp to 1 ton.
    There are no formulas, its worked out by experience.

    Cheers
    Derek

  3. #3
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    Nov 1999
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    Surrey, Canada
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    Default RE: Horsepower to Ton Ration Questions

    Chris,

    CPR has formulas for calculating haulage capacity for each subdivision depending on the ruling grade.

    I'll see if I can dig up the page from school that explains it all.

    Andrew Pickell

    [link:www3.telus.net/apickell/SquamishSub/bcrhome.htm|BC Rail Squamish Subdivision for MSTS]
    http://www3.telus.net/apickell/SquamishSub/banner.jpg

  4. #4
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    Falls Village, CT, USA.
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    Default RE: Horsepower to Ton Ration Questions

    >does that mean 3000 HP to 1 ton?

    Stop and think here Chris: One SD70MAC has 4200 HP. BNSF regualarly runs 130 car Coal trains (100 ton coal cars) on the Powder River Basin with 2 lead locos and either 1 or 2 DPU's on the rear.

    HP ratios are generaly (on CSX) between 1/2 HP per ton on lower priority or drag frights to 4 HP per ton on Z trains or high priority stack trains, etc.

  5. #5
    Join Date
    Nov 1999
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    near Jacksonville, TX
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    Default RE: Horsepower to Ton Ration Questions

    Speed and consist play a key role in this, as there is not much HP/ton needed to move any heavy train at 20 mph on level track, but you will see a big difference between say 50 30ton boxcars and 50 30ton TOFC at 70 mph. The TOFC have a lot more drag, and that increases by an exponent of 2 not linearly, as speed increases.
    Bob

  6. #6
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    Nov 1999
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    North Carolina, USA.
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    Default RE: Horsepower to Ton Ration Questions

    HP to weight can also be applied to highway vehicles. Most cars are going to be between a ton or two in weight. You've got to get to a very high-end car, and a pretty good-sized truck, to reach 300 HP, let alone 3000.

    Chris - didn't you say you drove semis? Think about the HP ratio for one of those rigs and compare to rail. That's one of the reasons rail is more efficient in getting stuff across the country. It's a bit harder to head off your usual route to get to a new customer, though...

    Andy

  7. #7
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    Default RE: Horsepower to Ton Ration Questions

    It didn't really apply to semis though. We had the same horsepower regardless of weather we were empty (14,000-17,000 LBs), loaded (80,000 LBs), or even overweight (92,000 LBs. Yes, 12,000 LBs over thanks to a mix up when we weighed out). Sure the truck would react differently to each load, but we couldn't control the horsepower ratio.

  8. #8
    Join Date
    Nov 1999
    Location
    Stevens Point, Wisconsin, USA.
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    Default RE: Horsepower to Ton Ration Questions

    I've seen tractors with double trailers on the highway in the last ten years, I guess the next logical step is doubleheading the tractors! :o

    Dunno if this will do you any good, but here's a HP/Tonnage calconfuser program;

    http://www.vcn.com/~alkrug/rrfacts/traincalc.htm

  9. #9
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    near Jacksonville, TX
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    Default RE: Horsepower to Ton Ration Questions

    Distributed power...

  10. #10
    Join Date
    Nov 1999
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    Augusta, Ga, USA.
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    Default RE: Horsepower to Ton Ration Questions

    New York, Ohio, and Ind. allow double 45' and 48' trailer combinations. You see it quite a bit here in New York, especailly with Wal-Mart having a DC nearby.

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