Re: Calculating Motive Power Requirements

John Larkin

It's been a long hot day but my math says a 110 car train of 286,000 lb hoppers would probably weigh in at 7800-7900 tons.  Given 3 units (2 front, 1 back) generating 12,000 hp, that more like 1.5 hp/ton. It's been many years (1982) but I seem to remember 4hp/ton being quite good for a hotshot running from North Platte to the Left Coast. 

John Larkin

On Friday, August 14, 2015 8:03 PM, "Tim O'Connor timboconnor@... [STMFC]" wrote:


My bad again -- I was quoting lbs-TE per ton not horsepower !!

So a loco with 22,500 lbs continuous TE on a 2% grade could lift 500 tons,
or about 10 "average" STMFC era freight cars.

The SP for example would assign five 2-10-2's to lift 50 car trains north
of Dunsmuir CA. A cab forward could take almost twice as much as a 2-10-2.
An ABBA F set could lift about twice as much as one cab forward.

On flat lands of course relative performance was very different than on
steep mountain grades.

Tim O'

At 8/14/2015 03:00 PM Friday, bill Vaughn wrote:
>Rules of thumb --
> 5 hp/ton on 0% grade (flat land)
> 25 hp/ton on 1% grade
> 45 hp/ton on 2% grade
> 65 hp/ton of 3% grade
>Tim I just retired off a class 1 mountain grade, I wish you had assigned us power. I have never seen anything near 25 hpt even on the hottest of trains. More like 4 to 5 hpt.
>Bill Vaughn

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