How to Calculate Pulling Power

Pulling power refers to the force an engine exerts on something and is commonly calculated for train engines. To calculate pulling power, you will need to take some measurements of the engine, as well as have the engine manual handy to determine the mean pressure of the engine piston. Once you have all the necessary variables, calculating the pulling power of an engine can be easily attained using a straightforward formula.

Things You'll Need

• Measuring tape
• Calculator
• Engine manual

Instructions

1. Measure the cylinder diameter, length of the engine stroke and the diameter of the driving wheels with the tape measure. You can also find these measurements in the engine manual.

2. Multiply the cylinder diameter by itself. For example, if the engine has a cylinder diameter of 10, then 10 x 10 = 100.

3. Multiply the number obtained in Step 2 by the length of the stroke and the mean pressure on the piston, which can be found in the engine manual. For example, 100 x 15 in stroke x 80 pressure = 120,000.

4. Divide the number obtained in Step 3 by the driving wheel diameter to get the pulling power. Using the above example, if the engine had a wheel diameter of 50 inches, then 120,000/50 = 2,400 pounds of tractive force.

References

• Catskill Archive: Power of Locomotives