Calculating Locomotive Tonnage Rating

[BigBoyFan4006]

I'm trying to find an equation that can give me the tonnage rating for a given locomotive, using the locomotive's traction effort/horsepower and the ruling grade of a route. I've searched on Google, and found some explanations as to how you would calculate the tonnage rating (including a couple threads here in the forums), but no defined equation. (I'm a numbers guy, so I like to know how to crunch my numbers.) Any help is appreciated!

EDIT: Would there also happen to be a similar equation for dynamic braking? Or would pulling tonnage and dynamic braking tonnage correlate?

 

[PRR1361]

The Encyclopedia Britannica (11th edition, c. 1911) has a lengthy article on how to calculate tractive effort of steam locomotives.

 

[denniscastle]

cant you just use a claculator? thats what i do in math class

 

[JCitron]

This might be helpful.

http://web.archive.org/web/20110726173109/http://www.alkrug.vcn.com/rrfacts/RRForcesCalc.html

Note I had to access the information via the web archive. The original website, unfortunately, is gone because Al retired.

John

 

[BigBoyFan4006]

cant you just use a claculator? thats what i do in math class

Yes, but unless you know the equation to use, you're not going to get the right answer. For example, your math teacher assigns you a problem that asks you to find the area of a triangle. You can use your calculator to help you find the answer, but if you only know how to find the area of a square, you're not going to find the proper answer.

This might be helpful.

http://web.archive.org/web/20110726173109/http://www.alkrug.vcn.com/rrfacts/RRForcesCalc.html

Note I had to access the information via the web archive. The original website, unfortunately, is gone because Al retired.

John

Yep, that'll help a lot! I'll just bookmark the individual page. Thanks a bunch!

 

[BigBoyFan4006]

After messing around with it a bit, the "Car Count" input is throwing me off. How are you supposed to know how many cars there will be in the consist unless you find the tonnage of a locomotive (assuming there will only be one locomotive in the consist)? Changing that value changes the output for tons in the calculation. Does the output mean tons per railcar depending on how many cars there are?