I.
FORM FOR RECORDING THE RESULTS OF EXPERIMENTAL TRIPS WITH LOCOMOTIVES.
In comparing the work done by different locomotives, we must know not only the relative amounts of material consumed, but also the exact nature of the work done, as depending upon speed, load, curves, and grades. The following blank, when filled, has been found to give complete information, for comparison.
| Station, | |
| Time of arriving, | |
| Time of departing, | |
| Time running, | |
| Time standing, | |
| Distance, | |
| Rise, | |
| Fall, | |
| Degrees of curvature, | |
| Equated distance, | |
| Cars taken, | |
| Cars left, | |
| Load between stations, | |
| Equated mileage of train, | |
| Gauge pressure, | |
| Notch of sector, | |
| Fuel used, | |
| Water used, | |
| Lbs. of fuel per gallon of water, | |
| Lbs. of fuel per equated mileage, per ton or per passenger, | |
| Comparative effect, |
K.
PROPER WEIGHT OF LOCOMOTIVES.
To move a given load the engine requires a certain amount of power; to exert such power there is needed load enough on the drivers to prevent slipping on the rail. This load varies from three times the tractive power, (in the best state of the rails,) to ten times the tractive power, and even more, (in the worst state). A fair working average (without sand), being one sixth; with sand, much less. Sand must be used upon grades and upon bad rails. To find then the proper weight, we have only to estimate the tractive power upon the hardest point of the road, and multiply it by six.
Examples.
How heavy an engine is needed to draw two hundred tons (including engine and tender) at twenty miles per hour over sixty feet grades?
The resistance on a level is
| 200 ×(20 × 20 171 + 8) = | 2,060 | pounds. |
| The resistance due to the grade | ||
| 200 × (60 5280 × 2240) = | 5,200 | pounds. |
| The resistance due to curves | ||
| 200 × 5= | 1,000 | pounds. |
| And the whole resistance, | 8,260 | pounds. |
| which multiplied by 6, is | 49,560 | pounds. |
or 22.1 tons, to which add 5 tons as the necessary load upon the truck, and the whole weight is 27.1 tons, which is the necessary weight of an engine to draw 200 tons over 60 feet grades, at 20 miles per hour.