43 RAILWAY CONSTRUCTION. 



bridges, as the same amount of waterway would have to be 

 provided in each case. 



The same remark applies to culverts and drains. 



There would, on the other hand, be a small saving in the 

 quantity of land to be acquired to the extent of a narrow strip 

 or zone, represented by the difference in width between the 

 narrow and standard gauges. 



There would also be the same small proportionate saving 'in 

 the embankments and cuttings to the extent of the difference in 

 gauge. 



Also a saving in the overline bridges and road approaches in 

 consequence of less width and height of the opening through 

 those bridges. 



And a saving in the rails, sleepers, and ballast of the per- 

 manent way, to the extent consistent with efficiency. That 

 some saving may be effected in these is undoubted, but it is 

 necessary to exercise caution, and not rush to the opposite 

 extreme by making the parts too light. A rail should be made 

 not only strong enough to carry well the engines that have to 

 pass over it, but it should also be heavy enough to stand the 

 wear of several years. Narrow-gauge engines must be heavy 

 in conformity with the loads they have to haul. The same 

 amount of power must be exerted to haul a hundred tons on a 

 given gradient, whether the gauge be narrow or broad. In some 

 cases of narrow-gauge railways the original rails, which weighed 

 only 45 Ibs. per yard, have since been replaced with others 

 weighing 60 and 65 Ibs. per yard. The light 45 Ib. rails were 

 evidently not found to be sufficiently heavy to keep the road to 

 proper line and level. The result of our everyday practice 

 seems to prove that there is not only an advantage, but an 

 economy, in adopting rails of a heavy section, and experience 

 would therefore indicate that even for a narrow-gauge railway 

 it may not be expedient to adopt rails weighing less than 65 

 Ibs. per yard. 



Gradients. There are very few localities where the rails on 

 any line of railway can be laid perfectly level or horizontal for 

 more than comparatively short distances. By far the greater 

 portion have to be laid on inclined planes of varying rates of 

 inclination to suit the general formation of the district traversed, 

 and the circumstances of the line to be constructed. 



The degree, or rate of inclination, of these inclined planes, or 



