Western Railroad Discussion > Why does BNSF use DC Power on Grain,Ethonal, and Crude Oil?

Hi Everybody. I know BNSF uses AC Power for coal trains. But why does BNSF use DC power on Grain, Ethonal, Crude Oil, Ore, Taconite, and other heavy unit trains?

One possible answer:

North American railroads such as BNSF, UP, and KCS have determined that A.C. is more cost-effective for heavy-haul trains such as coal, and D.C. more cost-effective for all other trains. NS has favored D.C. for everything and CSX A.C. for everything. The decision is based on the physical characteristics of the railroad, the operating plan, and the traffic mix.

The only difference in the way A.C. and D.C. run is that a train powered with A.C. locomotives can have a very low horsepower-per-ton ratio and still move without exceeding the heating limits on the traction motors. A.C. motors in fact can run to a stall at full current without damaging the motors, whereas D.C. motors will quickly overheat at low speeds and full current and experience fatal damage.

http://cs.trains.com/trn/f/741/t/112679.aspx

The fact is that the power dept. uses what's available. Yes, they have preferences just as engineer's do. DC units will still do the job.

Eng.Shadetree

ldstephey Wrote:
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> The only difference in the way A.C. and D.C. run
> is that a train powered with A.C. locomotives can
> have a very low horsepower-per-ton ratio and still
> move without exceeding the heating limits on the
> traction motors. A.C. motors in fact can run to a
> stall at full current without damaging the motors,
> whereas D.C. motors will quickly overheat at low
> speeds and full current and experience fatal
> damage.
>

Which works wonders on line capacity...which is paid for in a different budget.

TAW