148 BULLETIN 711^ IT, S. DEPARTMENT OF AGEICULTUEE. 



above the yarding engine. The trip line, which is strung near the 

 pole road in such a way that it will not interfere with the operation 

 of the main cable, leads through trip blocks located at suitable points 

 and then through the tail block, where it is attached to the woods- 

 end of the main line. The main cable follows the road and is kept 

 in place with blocks or rollers where turns are made. 



From six to eight logs, depending on their size and the character 

 of the road, are fastened one behind the 

 other by means of grabs or dogs (figs. 53 

 and 54), forming turns, which are attached 

 to the main cable. The turns are made up 

 by a grab man. A chaser follows the logs 

 to the landing, often riding in a rigging 

 sled hollowed out of a log, which is attached 

 to the rear log. He can signal to the road 

 engineer at any point along the line by pull- 

 ing on a wire which is stretched from the 

 road engine. On arrival at the landing the 

 chaser aids in placing the logs on the land- 



FiG. 53. — Coupling grabs. 



ing, removes the grabs from the logs, and. 



returns with the grabs in the rigging sled 

 to the yarding engine. In some cases, especially where the pole road 

 is so steep in places that gravity causes the logs to run faster than the 

 lines travel, the logs in the turn are not dogged up and pulled to the 

 landing. Instead, they are pushed into the landing, a 

 hock attached to the main line being made fast to the 

 rear log. By this method several turns of logs of the 

 ordinary size may be along the road at different points 

 at.one time. 



It is practically impossible to say how far a road en- 

 gine works on the average. Unless conditions are par- 

 ticularly favorable one machine will not be able to haul 

 farther than 3,000 feet; in many cases less than this. 

 At this distance a road engine should generally be able to handle 

 the output of two yarding engines. 



Fig. 54. — Log- 

 ging dog. 



EQUIPMENT. 



Boacl engines. — Sim.ple-geared, wide-drum engines are used for 

 roading, the size and drum capacities depending on the size of timber, 

 character of road, and length of haul. They are mounted on sleds 

 the same as ground yarding engines and moved over the ground from 

 one setting to the other by their own power. 



