ja RAILWAY CONSTRUCTION. 



provide refuge sidings, and slow trains have to be shunted from 

 one main line to the other to allow of fast trains passing them, 

 some simple arrangements should be supplied in the signal 

 cabins to help to remind the signalman of the shunted train. 



11. Efficient means should be adopted to prevent the 

 accidental opening of the doors of passenger trains. 



To carry out the undertaking, the engineer has to prepare 

 working plans and sections to a somewhat larger scale than that 

 adopted for the Government or Parliamentary plans, and on 

 which must be marked the exact positions of the commence- 

 ment of the curves, straight lines, and gradients. The sites of 

 all the over and under bridges must be shown, and their angles 

 of crossing noted. All road, river, or stream diversions must be 

 indicated, so that the work in connection with them may be laid 

 out on the ground. All culverts and drains must be marked, 

 and their size, depth, and direction described. Public road level- 

 crossings, and farm or occupation-road crossings, must be shown 

 in their proper positions. 



The face-lines of the ends of all tunnels should be marked on 

 the working plan and section, and the position of any shafts, 

 which may be intended either for use in carrying on the work 

 or for future ventilation. 



A considerable amount of investigation and negotiation will 

 have to be entered into before the locating of the above works 

 can be finally decided. The desire to meet the wishes and 

 convenience of all parties interested must of necessity be con- 

 trolled by the physical circumstances of each case ; very little 

 alteration can be made in the level of the rails, although some 

 variation may be made in their position. 



When fixing the depths of culverts and drains, attention 

 must be paid to any probable improvement in the drainage of 

 the district, which might at some future time necessitate the 

 deepening of such of the main culverts where the inverts had 

 been laid too high. 



Unless all these details are determined, and shown on the 

 working-plans before the works are commenced, there is the 

 risk that embankments may have to be opened out to admit of 

 bridges and culverts, and cuttings changed to permit of road 

 diversions. 



The entire centre-line of railway must be carefully staked 



