RAILROAD LOCATION AND CONSTRUCTION — MACKENZIE. 7^5 



Sometimes, in a heavy cutting, the track is laid over the top 

 of the hill, and some distance to one side, if it can be done with- 

 out exceeding a grade of 3 or 4 ft. per 100, and steam-shovels 

 are put to work at both ends, while the material is hauled away 

 by locomotives and cars to make embankments at a distance. 

 For this purpose temporary trestles are built over unfinished 

 culverts and over depressions near which no material is obtain- 

 able for embankments. These trestles are finally left in place 

 when banks are completed. 



Ballasting. — Gravel ballast is generally brought by train. It 

 is loaded on the cars by a steam-shovel, and unloaded by a plow, 

 or by side-dump cars. The track is lifted twice, and the ballast 

 packed under the ties with shovels, to a depth of 12 or 14 inches. 



Approximate cost of grading the Road-bed : — 



Kind of material. Price per cubic yard 



Earth in cuttings 22c. to 28c 



Frozen earth 31c. additional. 



Earth in foundations 30c. 



Hard clay 35c. 



Hard pan 55c. to 70c. 



Rock (loose) 55c. to 70c. 



Rock (solid) $1.15 to §1.50. 



Excavation in water SOc, plus dry price. 



Extra haul over 1000 ft f c. per c. yd. over 1000 ft. 



Filling by train from borrow-pit 1000 ft. from centre of 



bank 35c. 



do. do. (3 mile haul) 40c. 



Ballast 30c. 



Box Culverts. — Dry stone work for box culverts has had its 

 day, and it is not probable that in future it will be used to any 

 great extent in this country. Culverts are now laid in lime and 

 cement mortar, designed to vent water under a head, as an iron 

 pipe would ; no dry stone culvert can do this, and the attempt 

 generally results in a washout. The side walls of box culverts 

 are extended out beyond the end, or head walls, equal to height of 

 culvert, so that in freshets, the opening cannot be obstructed by 



