LOCATION. 11 



Ing points. Commercial centers, stream crossings and con- 

 trolling elevations form the principal controlling points. 



Mountain locations are subject to greater restrictions, and; 

 arc usually fixed with reference to the position and height of 

 the summit, the distribution and amount of rise and fall to be 

 overcome, and the relation between the adopted gradients and 

 the corresponding length and cost of line. 



The summit is, of course, the principal controlling point; 

 other points are generally accidental or artificial, as deter- 

 mined by local topographical conditions and the rate of grade- 

 adopted for the descent. Such lines are usually located de- 

 scending from the summit along a uniform grade contour to 

 an intersection with the "bottom" line of lower grades. 



All locations should be made with regard to future perman- 

 ent construction and every effort used to reduce the amount 

 of temporary construction which may be required to the least 

 limits. Many opportunities for stream diversion are neglected, 

 even in cases where the cost of the bridging otherwise required 

 Is many times in excess. 



When construction funds are limited, adopt lower stand- 

 ards of construction, lay temporary gradients and use short 

 sections of temporary line around or over tunnels and sections 

 of heavy work, if necessary to avoid sacrificing future bene- 

 fits arising from a properly located route. Such lines may be 

 economically revised at some future time, while the revision 

 of a generally faulty "location" might involve such large ex- 

 penditure as to make a remedy forever impracticable. 



Exercise extreme care in fixing the locations for stations, 

 water tanks, coaling plants and crossings, and in adjusting 

 grades for same, to reduce the cost and disadvantages of train 

 stops to the minimum. 



Train stops on or near the foot of grades should always be- 

 avoided if possible, and when not avoidable for any reason, 

 the rate of grade should be compensated to facilitate the start- 

 ing of trains. 



A proper reconnoissance report conveys a graphic im- 

 pression of the features of the region and route traversed, 

 and contains the fundamental elements affecting operation and 

 construction cost. The engineer should separate the routes re- 



