116 On Railway Gradients. 



in an incline of 1 in 50, 44.8 lbs. per ton ; hence, the surplus 

 of traction in a train of 150 tons, ascending an incline of 1 in 

 50, on account of grade, is 6720 lbs., or equivalent to the force 

 an engine requires to exert in moving 840 tons on a level. 



It would be but travelling over ground, thoroughly investi- 

 gated, to enter fully into the question, of resistances Peculia- 

 rities of climate and temperature occur in every habitable 

 portion of the globe. In England, the frosts, fogs, and mist, 

 are very detrimental to the expeditious ascent of inclines, and 

 involve a serious loss of power on the average working of 

 Trains. 



In Victoria, I do not anticipate from these causes, any material 

 loss, the climate is more genial, clear, and dry ; in summer 

 the heat of the furious Sirocco from its rarifying qualities, will 

 assist, rather than retard the engine, in climbing the steep 

 sudden ascents peculiar to this country. 



The full solution of the subject of gradients involves the 

 consideration of the question: — what incline gives practical 

 assistance to a descending Train ? 



The angle of Eepose has been assumed by various autho- 

 rities of inclinations, varying from 1 in 280 to 1 in 380 ; the 

 latter is an American standard. 



This is a question of great mathematical interest, and would 

 require too much time to enter upon fully. I am, however, 

 inclined from continued observation, to think the angle of 

 repose should be more acute than either of these inclines. It 

 is true, in practice, it cannot be supposed that any machine or 

 moving body can be made so perfect in form and finish, that it 

 will from a state of rest, move by force of gravity on an incline 

 more acute than 1 in 280, and run downwards with accelerated 

 velocity ; still, I have no hesitation in affirming, that the time 

 will come when the practice and theory of this subject will 

 much more closely assimilate than they now do. 



The Irish Railway Commissioners assumed, that a descending 

 grade of 1 in 140, imparted an impetus to a train, of practical 

 value, but with a greater incline no advantage was gained as 

 regards speed. From my own experience, I am led to infer, 

 that this standard is far too high, and should be about 1 in 100. 



The compensating power of descending planes, is an element 

 in their favour of the greatest importance, it being found that 

 the cost of the additional power required of an engine in 

 ascent, is nearly counterbalanced by an equivalent obtained in 

 descent, where a greater speed at a reduced cost is a natural 

 consequence. 



