230 BULLETIN 711, U. S. DEPARTMENT OF AGRICULTTJRE. 



when the car stakes are cut or tripped or the binder chains loosened. 

 The remainder are pushed from the cars with logging jacks. 



At one camp where unloading is done with this method, a crew 

 of three men — two brakemen and a dump man — unload eight cars, 

 averaging about 7,500 feet to the car, in about 30 minutes. The 

 dumping is seldom accomplished in less than 20 minutes, and it 

 sometimes takes an hour. The cars are equipped with patent stakes. 

 Considerable time is lost because the brow skid is too high. The 

 logs average about 2,000 feet in volume. 



TILTING DUMP. 



The tilting dump is used by a few operators. The dump is usually 

 built in paired sections, each 40 feet in length, with 30 feet of sta- 

 tionary track between. This arrangement permits logs of any length 

 to be dumped. Two cars loaded with 40 foot logs can be dumped at 

 the same time. When the logs are longer, one load is dumped at a 

 time, a truck being " spotted " on each of the two sections, which are 

 tripped simultaneously. 



Piles capped with timbers form the foundation. The roller tim- 

 ber — a stick 42 feet long and 20 inches square — and two stringers, 

 supporting a floor of ties and the latch stringers, form the platform 

 of the dump. The five latch timbers on each section of the dump 

 extend about 2 feet beyond the ties on the land side and are fastened 

 down by means of iron latches. This arrangement holds the sec- 

 tions level when the loads are run on. The center latch timber, 

 which is known as the trip timber, is longer and larger than the 

 others, being 36 feet long, 9 by 18 inches at one end, and tapering to 

 9 by 12 inches at the other, or latch, end. The roller timber works 

 on heavy cast-iron chains which rest on the sills. 



The operation is simple. When the cars are spotted, the chains 

 taken down, and the latches knocked off, gravity causes the dump to 

 revolve 15 degrees on its axis, rolling the logs from the cars. This 

 action is due to the fact that the center of the track is placed about 

 3 inches from the center of the roller timber on the water side. The 

 dump is brought back into position by the workmen walking out on 

 the trip timber. Loads heavy on the land side will not trip the 

 dump. Under such conditions, the tilting action is started by lifting 

 up on the trip timber. Slabs will not always roll off at the inclina- 

 tion provided, making it sometimes necessary to use a gin pole and 

 parbuckle line. The design of the dump is shown in a general way 

 in figures 75 and 70. 



At one camp which uses this method, three men — two brakemen and 

 the locomotive fireman — dump the logs at the rate of one car per 2^ 

 minutes, a large part of this time being consumed in taking down and 



