Western Railroad Discussion > Locomotive Torque quetsion

Today me and my friend went down to the BNSF yard to do some foaming. He is not a foamer but im starting to convert him, hahaha. We were discussing the Horsepower that the locomotives have and the question came up, "How much torque does an average unit have?" Does anyone here know? Thanks.

-Jacob Klatt
http://www.jkchubbes.com/

jkchubbes Wrote:
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> "How much torque does an average unit have?" Does anyone here
> know?

Torque is not as significant on a locomotive as it is on an automotive engine. This is because a locomotive has an electric transmission, and can always run at its peak horsepower output, unlike a car with a mechanical transmission. Horsepower is the most important measure, as it rates how much work a locomotive can do in a particular period of time.

Torque is essentially the tractive effort of the locomotive, which is highest at low speeds.

If you want to look at the engine alone, the torque at maximum engine speed can be calculated from the rated horsepower. On a 4400 HP locomotive, as an example, the maximum RPM is about 900. Therefore, the torque would be about 25,700 ft-lb.

Torque = HP * 5252.11 / RPM

Horsepower and tractive effort.

http://www.alkrug.vcn.com/rrfacts/hp_te.htm

AAK Wrote:
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> Horsepower and tractive effort.
>
> http://www.alkrug.vcn.com/rrfacts/hp_te.htm

That's a pretty nice explanation, Al. I sure wish I had something as clear and as practical back when I was taking my introductory physics/mechanics course in university.

Ray