RULES FOR CALCULATING THE STEAM ENGINE. 227 



the plane corresponding to an ascent or descent of unity. The quotient will be the force in 

 fts. acting down the plane. 



Example. Let the engine be 12 tons, the tender 7 tons, and the carriages and load 105 

 tons; and suppose the inclination of the railway to be 1 in 128. 



Engine 12 tons. 

 Tender 7 

 Train 105 



Gross load 124 

 Multiply by 2240 



4960 

 248 

 248 . 



128) 277760 (2170 tfcs., the force required. 

 256 



217 

 128 



896 

 896 



27. To find the tension on the circumference of the driving wheels, or the resistance to 

 traction. 



RULE. Multiply the gross load, expressed in tons, by 8, and the product will be the 

 number of tfcs. resistance if the engine and train move horizontally : for ascending an inclined 

 plane the effect of gravity, calculated by the last rule, must be added; and for descending an 

 inclined plane the effect of gravity must be subtracted. 



Example. Take the same case as before. 



Engine 12 tons. 

 Tender 7 

 Train 105 



124 



8 



992 fts. traction on a horizontal line of railway. 



If the engine and train be ascending an incline of 1 in 128, we have by the example of 

 last rule, 



Effect of gravity 2 1 70 Ibs. 

 Add 992 



3162 Ibs. traction up the plane. 



