RAILWAY CONSTRUCTION. 191 



purchased at a less price per ton than the iron rails of twenty 

 years ago. 



It is interesting to note that out of the many varied sections 

 that have been designed, some of which are shown in the 

 sketches described, only two have practically survived the bull- 

 head rail and the flange rail. The bull-head rail, Fig. 261, has 

 grown out of the original double-head rail, which had both the 

 top and bottom members made to the same section and weight, 

 with the object that, when the upper table had become so much 

 worn as to be unfit for further use, then the rail could be turned, 

 and the other table, or head, brought into service. Experience, 

 however, proved that turned rails formed a most uneven and 

 unsatisfactory road, the long contact with the cast-iron chairs 

 resulted in serious indentations at the rail-seats, rendering the 

 rails totally unfitted for smooth running. In practice, therefore, 

 it has been found better to restrict the running wear to one 

 head only, and to give increased sectional area to that head, 

 and, at the same time to diminish the sectional area of the 

 lower member to a corresponding extent, but to retain the same 

 width, so as to obtain a full bearing surface on the cast-iron 

 chair. Steel bull-head rails are now adopted on nearly all the 

 principal lines at home, and on several of the leading lines abroad. 



The flange rail, Fig. 265, was designed to give a broad, direct 

 bearing on the sleepers, and thus avoid the necessity of using 

 chairs. Rails of this section have been laid down on many of 

 our lines at home, and are very largely used on the Continent, 

 in the United States of America, and in our colonies generally. 

 This section is, also, nearly always adopted for narrow-gauge 

 railways. Having fewer parts, it makes a cheaper road than 

 the bull-head rail, but is not considered so strong or suitable for 

 heavy and fast traffic. Comparing the two rails shown in Figs. 

 261 and 265, each having exactly the same size and sectional 

 area in the head, it will be seen that there is more material in 

 the lower member, or flange, of the one rail than there is in the 

 lower member of the other; the weight per lineal yard being 

 79 Ibs. for the former and 75 Ibs. for the latter. But this small 

 excess in the weight and cost of the flange rail falls very short 

 of the cost of the cast-iron chairs and wooden keys necessary 

 for the bull-head rail. 



Up to the years 1870-1875, it was the common practice to 

 make the top, or wearing surface of the rail, comparatively 



