16 LOCATION. 



number of days in the year, the result will be the annual sav- 

 ing or added cost, resulting from such change in rate. Ta 

 obtain the capitalized value, divide this result by the proper 

 interest rate. 



When actual values are not known, assume the rate of 60c. 

 per train mile (see Volume of Traffic), which capitalized at 

 6% is $3,650 (one way only). 



The cost of operating heavier engines, assistant engines and 

 all other items of expense added or saved, should be computed 

 in addition and capitalized, if necessary (see Volume of 

 Traffic). 



Every effort must be made to maintain the lowest prac- 

 ticable and economical rate of grade over the entire engine 

 district. 



When sections of high grade are unavoidable, it is fre- 

 quently practicable to concentrate such "rise and fall" into 

 short sections, which may be economically operated by use of 

 assistant engines. 



The ruling grade of each engine district should be adjusted 

 with reference to those of the adjoining districts, or to con- 

 ditions of local traffic, in such a manner as to avoid unneces- 

 sary "breaking and making up" of trains. When not practi- 

 cable to secure this by grade adjustment alone a combined 

 adjustment of grades and engine, weights will effect the same 

 end. 



The ratio of rates of ruling grades to each other at points 

 of intersection should preferably be in proportion to the trac- 

 tive powers of the available types of engines. 



On sections of great rise and fall (mountain crossings, etc.) 

 it should be the aim of thje engineer to produce the maximum 

 and minimum ruling grades to an intersection, if possible, and 

 in any event to reduce the sections of different rates to the 

 least number. 



Ruling grades may be of different rates, but equal limiting 

 effect, when adjusted for unbalanced volume of traffic. 



Train stops on maximum grades must be compensated as 

 fully as practicable, and not less than 3.5 ft. in any case. Com- 

 pensation is not only provided for the increase in starting 

 friction over rolling friction, but in addition to permit trains 



