W being the weight of the train in tons, and R the resistance in lbs. per ton; found by the formula
V2
171 + 8 = R.
By this formula is formed table 1, giving the traction required to move trains of from fifty to one thousand tons weight, at speeds from ten to one hundred miles per hour.
No. 2.
349. To find the traction due to a grade.
Formula.
W × R
L,
where W is the weight of the train in tons, R the rise, and L the length of the incline. By this rule is formed table 2, giving the necessary traction to overcome grades from ten to one hundred feet per mile, with loads from one to one thousand tons.
To obtain the whole traction required, add the amounts taken from tables 1 and 2; thus the traction necessary to draw five hundred tons at twenty miles per hour over fifty feet grades is,
| By table 1, | 5,170 | lbs. |
| By table 2, | 10,605 | lbs. |
| In all, | 15,775 | lbs. |