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# Re: TRAINS - Correction

Some clarification

So here is the actual statistic not confused by fading memory, I still
think
it is impressive:

One can transport 1 ton of freight 100 km with 14 oz of diesel fuel, by
freight train.

That is a really interesting combination of units. But what does it mean?
Is it the marginal fuel used to move that much cargo, over and above that
used just to get the locomotive and the railroad car there? Does it depend
on the length of the train? If I am hauling a fully loaded 150 car train
and add 1 ton to one of the cars, do I use 14 oz. more fuel per 100 km? Or
is it the total fuel to move the train per ton of cargo carried? This sound
impressive but it may be considerably less so when put in the context in
which it was derived.

The context of the quote is as follows: It comes from the book "How to Wage
War", by James Dunnigan and occurs in a section on logistics, specifically
on the problem of moving supplies around and is comparing various modes of
doing this, trains to trucks to airplanes. Whether this comes from military
sources or civilian sources, I do not know, but might speculate that it is
from military sources; from the odd combination of units. The military is
fairly ensconced with SI for length units.

I would also speculate that this figure must come from a typical size train
(whatever that is, 20-100 cars perhaps) and amounts to the total freight
weight divided by fuel burned for a 100km trip. I don't know this for
certain, but its the way I'd calculate it, particularly if I were trying for
a figure that would compare how efficient it is, by different modes, to
deliver tonnage to an army in the field.

Joel