RAILWAY CONSTRUCTION. 



199 



Briefly summarized, the principal advantages and disadvan- 

 tages of the two kinds of rails stand as follows : 



ADVANTAGES. 



Bull-head BaiL 



Largo bearing surface of chair upon 

 the sleeper, and greater stability of the 

 rail. 



Longer life of wooden sleeper. 



Impossibility of rail tilting over out- 

 wards. 



Facility for changing a rail without 

 disturbing the fastenings in the sleepers. 



Easier to maintain, owing to less 

 disturbing strains on the fastenings. 



A bull-head rail is more readily set 

 or laid to follow line of curve. 



In most cases the one set of chairs 

 will serve for a second set of rails. 



Perfect straightness of rail : it is 

 very rare to find a crooked bull-head 

 rail. 



Easier to roll, and more likely to 

 obtain uniformity of steel. 



Flange Rail. 



Fewness of parts, and less cost. 



Smaller quantity of ballast required 

 to cover up the foot of rail. 



More lateral stiffness than the bull- 

 head rail. 



DISADVANTAGES. 



Bull-head Rail. 



Greater cost. 



More ballast required to cover up 

 the rail. 



Less lateral stiffness than the flange 

 rail. 



Flange Rail. 



The small rail-seat area on sleeper 

 throws great crushing weight on the 

 timber. 



Shorter life of wooden sleepers from 

 the cutting down of rail-seats. 



The edge of flange cuts the spikes 

 after a few years. 



The undulation of the rail under 

 trains tends to raise the spikes, and 

 causes lateral movement in the rails. 



More difficult to maintain, in conse- 

 quence of greater tendency of the fasten- 

 ings to work loose. 



Difficulty in getting flange rails 

 straightened laterally. 



More difficult to set to follow regular 

 line of curves. 



More difficult to roll, and less likely 

 to obtain uniformity of steel. 



Tramway Rails. Tramways on streets or public roads are 

 now universally recognized as important branches of the railway 

 principle. Their smoothness of movement, increased accommoda- 

 tion, and many other advantages as compared with the old road 

 omnibus, render it no longer necessary to call for special advocacy 

 when there is a possibility of their introduction. They occupy 



