236 BULLETIN 711^ U. S. DEPAETMENT OF AGEICULTTJEE. 



the attachment of a collar with ball bearings. The rest of the shaft, 

 or the part which is 10 inches in diameter, is set in a concrete base, 

 high enough to allow the arms to clear the bunks, and far enough 

 from the track to permit either arm when at right angles with the 



track to reach 1 foot be- 

 yond the outer rail. The 

 concrete base is 9 feet 

 square at the bottom and 

 6 feet square at the top. 

 The repelling ends of both 



Fig. 78. — Ground plan of two-poke log unloader. 



arms are fitted with steel castings. 

 These steel castings have sharp cut- 

 ting edges, one of which engages a 

 load of logs as the train moves to- 

 ward the unloading device, penetrat- 

 ing the nearest' log, thereby doing 



away with the ne- 

 cessity of attaching 



the arms to the car 



by a cable or some 



other method. 

 In unloading the 



train moves toward 



the unloader slowly, 



seldom finding it 



necessary to stop. 



The average time 



consumed in un- 

 loading 15 cars of 



logs, containing approximately 70,000 feet, is about 



8 minutes, which includes the coupling of cars, 



knocking out the blocks, etc. 



The cost of making and installing the machine 



described above amounted to $1,000; $900 for mak- 

 ing and $100 for installing. At the end of three years of use nothing 

 had been spent for repairs. The cost of operation, other than train 

 crew labor, consists of about one gallon of lubricating oil per year. 



-Cross section of two-poke 

 lopT unloader. 



Fio. 80. — Counter- 

 weight pile, two- 

 poke log unloader, 



