142 BULLETIN 711, V. S. DEPAETMENT OF AGRICULTUEE. 



of its life when it was discarded a.nd used for chokers. The wear 

 on this line is much greater when yarding uphill or on level ground. 

 Still, in no case is its life as short as the main yarding lines used 

 for ground yarding. The haul-back lines in use range from nine- 

 sixteenths to twelve-sixteenths inch in diameter. Straw lines are 

 generally three-eighths inch in diameter. 



SWINGING. 



Among the loggers of the region it is generally considered good 

 practice to build railroads within an economical j^arding distance 

 of the timber.- It is not always possible, however, to do this. It 

 may be cheaper, because of the cost of railroad construction or the 

 quantity of the timber, to use two or more logging engines, with or 

 without improvements, to transport the logs from the stump to the 

 landing. The practice of using two or more engines to transport 

 timber over the ground — that is, without improvements — from the 

 stump to the landing is known both as swinging and roading. In 

 this publication the operation will be referred to as swinging, the 

 distance from the yarding engine to the landing or pole road being 

 considered as the swinging distance. The use of overhead logging 

 engines for the same purpose will also be considered as swinging. 



The distance it pays to swing timber is governed largely by the 

 topography and formation of the country and by the quantity of 

 timber in the swinging unit that can not profitably be logged direct 

 to the landing. Under most conditions timber can be swung farther 

 with overhead than ground logging engines. 



Swinging decreases the cost of railroad construction, but it in- 

 creases the cost of transporting the logs from the stump to the land- 

 ing. Theoretically speaking, it is the comparison of the cost of the 

 two methods, taking into consideration the fact that the yarding and 

 swinging at times delay each other, that indicates whether swinging 

 should be resorted to in a given case. 



GROUND SWINGING. 



It has at times been found profitable to swing logs three or four 

 thousand feet over the ground. At times it may prove cheaper to 

 single-haul the timber 1,200 feet or more — if the drum capacity of 

 the yarding engine will permit — ^than to double-haul it. At other 

 times it is cheaper to double-haul a shorter distance than this. Not 

 infrequently two swing engines, in addition to the yarding engine, 

 are used, and occasionally three swing engines are necessary. 



The distance between the swing engines depends to a great extent 

 on the topography of the country, the aim being to place them in 

 such a way that they will not hold up the yarding engine. Under 



