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.

Or, generally,

Let W = Weight of engine, tender, and train, in tons,
Let V = Speed in miles per hour,
Let a
b		 = Fraction expressing the grade,
Let c = Resistance, in pounds per ton due to the sharpest curve, which, assume as 5 lbs., as we have no reliable data,

and we have, as the weight of the engine,

[W(V2
171 + 8) + a
b × 2240 + 5]6/2240 =

weight of engine exclusive of weight on truck.

If we assume the adhesion as one fourth of the weight on the drivers, and load 150 tons, speed twenty miles per hour, and grade forty feet per mile, the above formula becomes,

[150(20 × 20
171 + 8) + (40
52802240) + 5]4/2240 =

nine tons nearly.

To which add five tons, and we have as the whole weight, fourteen tons.

Fig. 158.

TRANSCRIBER’S NOTES

  1. Made corrections listed in Errata beginning on p. xv.
  2. Did not correct the error for page 32 line 2 as it referred to the cut rather than the text.
  3. Rotated images with text in the image so the text was right side up.
  4. Changed “area 2,827 miles” to “area 2,827 square miles” on p. 4.
  5. Added “GENERAL TOPOGRAPHY” subheading on p. 12.
  6. Changed “11480.667” to “11,480,667” on p. 40.
  7. Changed “+ 5,297.334 + 4,437.334” to “+ 5,297,334 + 4,437,334” on p. 54.
  8. Added “SLOPES” subheading on p. 89.
  9. Added “FORM OF RAILROAD SECTIONS” subheading on p. 97.
  10. Added “ROCK EXCAVATION” and “BLASTING AND QUARRYING” subheadings on p. 115.
  11. Added “SIDINGS AND CROSSINGS” subheading on p. 298.
  12. Changed “18.24 cubic feet per hour” to “18.24 cubic feet per hour of water” on p. 304.
  13. Changed all commas to decimals in the table's right-hand column titled “Resistance in lbs. per ton” on p. 314 to agree with the previous expression.
  14. Added “RETARDING OF TRAINS” subheading on p. 401.
  15. Added “CLASSIFICATION OF BUILDINGS”, “LOCATION OF BUILDINGS”, and “TERMINAL PASSENGER HOUSE” subheadings on p. 403.
  16. Added “TERMINAL FREIGHT HOUSE” and “ENGINE HOUSE AND APPURTENANCES” subheadings on p. 405.
  17. Added “WOOD SHED AND TANK” subheading on p. 407.
  18. Silently corrected typographical errors.
  19. Retained anachronistic and non-standard spellings as printed.