112 RAILROAD LOCATI(3N AND CONSTRUCTION — MACKENZIE. 



Preliminari/. — Next comes the preliminary survey, where the 

 transit and level are employed. If location is at all likely to 

 follow, an ordinary compass should not be used. The transit 

 should l)e provided with a gradienter and a level on the telescope. 

 The gradienter is very useful wdien running to a maximum grade. 

 The jDreliminary should be run with such care that it will not 

 deviate from the final location more than 200 or 800 feet at any 

 point. 



I will here give a description of the running of both prelimin- 

 ary and location simultaneously, hy the writer. After the 

 general reconnaissance had been made, and certain ruling points 

 fixed, and wdien the preliminary party had been at work for one 

 day, a location party was started. The engineer in charge pro- 

 vided himself with a wooden box 21"x28" and If" thick, holding 

 about 20 sheets of common drawing-paper, a brass ruler, protrac- 

 tor, 12" scale, and a pair of 6" compasses. On the front edge of 

 the box were fastened a pair of leather handles, and a pair of 

 brass hinges on the other edge. When this box was opened out 

 and set up on four pegs, under the grateful shade of some wide- 

 spreading tree by the boy who carried it, the engineer's office was 

 located there for the time. 



The engineer was almost constantly with the preliminary party, 

 and gave directions to the location party from his own general 

 notes and the results of the preliminary work. Tlie sheets 

 already referred to were 20"x27" in size, numljered from up- 

 wards. Every evening the transit-man of the preliminary party 

 plotted his notes on these sheets, to a scale of 200 ft. to a.n inch. 

 As the sheets were finished they were handed to the topographer, 

 who recorded on both sides the line, the rise or fall above or below- 

 each station, or at distances two or three stations apart as the 

 case might be, according to the roughness of the ground. These 

 notes generally extended 100 to 300 ft. on each side of the line. 

 While this was being done, the leveler had plotted up his profile. 

 The engineer, then, with the help of the plan and profile, and a 

 fine silk thread, laid down roughly the l)est grades possible 

 between the most abrupt points on jjrofile, and dotted on the plan 

 the line which would give the least cut or fill for this grade. 



