RAILWAY CONSTRUCTION. 65 



expeditiously, as one set of men can be engaged advancing the 

 gullet and laying the track, while others are following up 

 and taking down the sides. A large number of waggons can 

 thus be filled in a day, and a small locomotive kept fully 

 employed. 



Occasions will arise where the material from a large cutting, 

 situate on a continuous gradient, as in Fig. 55, has to be carried 

 in both directions to embankment. 



In wet weather, or if the cutting is at all wet, it would be 

 almost, if not quite, impossible to carry on the excavation at the 

 upper end to the proper formation level. The water would 

 collect at the lower level, and not having any means of escape, 

 except by pumping, would stop the work. In such a case the 

 best way is to take out the cutting at the upper end to a slight 

 rising gradient, as shown in the sketch, sufficient to carry away 

 all water, and afterwards take out the lower portion in the work- 

 ing from the other end of the cutting. 



Cases will arise where it will be necessary to make a shallow 

 cutting through boggy peaty ground. If the boggy material be 

 very soft, and its thickness from the formation level to the solid 

 ground below be not great, it may be advisable to remove this 

 extra thickness down to the hard lower bed, and fill in up to 

 formation level with strong material. If, however, the bog or 

 peat be too thick to justify its entire removal, it should be 

 excavated say down to two feet below formation level, and a 

 thick layer of branches of trees and strong brushwood closely 

 laid and packed the full width of the road-bed. On this prepara- 

 tory foundation must be placed good clean ballast to carry the 

 permanent way. Two or three extra sleepers should be allowed 

 to the rail length, and in some instances it will be necessaiy to 

 introduce two, or even four, rows of strong longitudinal timbers 

 half balks under the transverse sleepers. The object of all 

 this extra timber is to obtain a large increase of bearing area on 

 the soft yielding surface of the boggy material. Notwithstand- 

 ing these special precautions, the trackway will sink down a 

 little during the passage of an engine or train, but will generally 

 return to its former level. Good side drains or water tables 

 should be formed at- each side of the cutting to take away all 

 rain and surface water. 



In all cuttings it is desirable to have the line of formation on 

 a slight gradient, sufficient to carry away all rain water or spring 



