48 BULLETIN 440, U. S, DEPARTMENT OF AGRICULTTJEE. 



Grades and curvature may be heavier on spurs than on the main 

 line where heavier loads must be handled. A geared engine can 

 negotiate heavier grades and sharper curves than a rod engine. 

 Narrow-gauge equipment can foUow sharper curves than standard. 



Except where topographic conditions forbid, long main-line log- 

 ging railroads are usually constructed to permit the use of rod engines. 

 The maximum grades allowed are 3 or sometimes 4 per cent empty 

 and 1 per cent loaded. The sharpest curves are usually 16° for 

 standard gauge and 20° for narrow gauge.^ In rougher regions 

 even main lines can not be constructed for rod engines at a reasonable 

 cost and geared engines must be used. The maximum grades ordi- 

 narily employed are 5 per cent empty and 2 per cent loaded. A 

 heavier grade than 5 per cent can be surmounted, but it is difficult 

 to hold a heavy train on the down grade. The maximum curves 

 used are from 25° to 30° for standard gauge and from 30° to 40° for 

 narrow gauge. 



Logging spurs are usually constructed for the use of geared engines 

 with a few cars at a time. The usual maximum grade for empties 

 is 7 or 8 per cent, or even 10 per cent on short pitches, and the maxi- 

 mum for loads about 4J per cent. The usual maximum curve for 

 narrow-gauge spurs is 50°, though in some instances curves as sharp 

 as 60° are used. The maximum for standard gauge is about 40°. 

 One company using saddle-tank dinkey rod locomotives with a wheel 

 base of 8 feet constructs its narrow-gauge logging spurs with maximum 

 grades of 5 per cent empty and 2 per cent loaded and a maximum 

 curvature of 50°. The maximum grades given above are of course 

 compensated on curves at the rate of from 0.02 to 0.03 per cent per 

 degree. 



All of the larger companies employ competent woods engineers 

 to lay out their railroads. The engineers cooperate with the woods 

 superintendent in determining roughly the routes of main-line exten- 

 sions and spurs. The engineering force then makes prehminary 

 and permanent location surveys and exercises general supervision 

 over the construction. Upon the larger operations the engineer has 

 a crew of a transitman and two helpers. The engineer is usually 

 employed the year round and devotes his time in winter to mapping 

 and cruising. During the summer considerable time of the engineering 

 force IS devoted to rumiing land Hues and other activities apart from 

 railroad construction. The cost of engineering upon logging railroads 

 varies from $200 to $400 per mile for main lines, depending upon the 

 difficulty, and from $125 to $250 per mile for spurs. In the construc- 

 tion of commercial railroads it is usually customary to figure engineer- 

 ing as 5 per cent of the other costs. 



' straight cormected saddle-tarLk locomotives with a short wheel base can be operated over sharper curves 

 than these. 



