182 BULLETIN 711, U. S, DEPARTMENT OF AGRICULTUEE. 



Methods of location. — The engineering steps preceding tlie build- 

 ing of logging railroads, while not always so clearly defined or per- 

 formed in the same way, are in general the same as those preceding 

 the construction of a common carrier railroad. They are («•) recon- 

 naissance, (b) preliminary survey, and {c) location. 



The reconnaissance in the case of main-line logging railroads con- 

 sists of a more or less rapid examination of possible routes, with the 

 following objects in view : To determine the most feasible and eco- 

 nomical line between the timbered area and the delivery point; to 

 locate the controlling points, which consist of stream crossings, sum- 

 mits of ridges, and other natural or artificial features of the territory 

 through which the road must necessarily pass in order to make the 

 largest amount of timber accessible ; to determine the maximum grade 

 and the maximum degree of curvature ; to ascertain the kind of mate- 

 rials likely to be encountered in the construction of the road to deter- 

 mine the effect of the materials on the cost of maintenance; and to 

 obtain a general idea of the approximate cost per mile of the com- 

 pleted road. This constitutes in the main the field work performed 

 by a timber appraiser. From the information so secured, together 

 with information usually secured by a preliminary survey, he must 

 estimate the approximate cost of the main line. 



For the purpose of determining relative elevations, maximum 

 grades and curves, the directions of streams and roads, etc., the timber 

 r.ppraiser usually provides himself with an aneroid barometer, a 

 pocket compass, and a hand level. With this equipment he person- 

 ally investigates all important points involved and makes compre- 

 hensive notes of all topographic features along the route, such as the 

 size and direction of streams, together with their high-water marks; 

 the slope of important waterways that must be crossed ; and any other 

 information concerning them that can be secured. Such information 

 as can be secured regarding the character of the soil and the preva- 

 lence of rock is carefully noted. In addition the appraiser notes the 

 probable quantities of excavation, embankment, and bridging per 

 mile; also any other data which will assist him in estimating the 

 cost of the proposed railroad. 



The method in the case of spur railroad is in large measure the 

 same as that used for the main line, in that some one determines, 

 after making an examination of the tract to be logged, the general 

 routes of the main spurs. 



Many operators in the region consider topographic maps an essen- 

 tial part of their equipment. These are prepared in connection with 

 the timber cruise, or by engineers before the tract is opened up, the 

 contour intervals ranging from 10 to 50 feet, depending on the 



