RAILWAY CONSTRUCTION. 197 



head rail has at least double the bearing surface on the sleeper 

 to that of the flange-rail seat, so that under the same circum- 

 stances of rolling load as above described, the weight of 134 Ibs. 

 per square inch would be reduced to half, or 67 Ibs. The 

 greater length given to the chair effectually prevents any 

 rocking action on the part of the rail, and reduces to a minimum 

 any lifting action on the spike. A good fitting chair especially 

 when keyed on the inside provides a most effectual support to 

 the rail both vertically and laterally, and maintains the rail to 

 accurate gauge. By giving proper clearance space at the tops of 

 the chair-jaws, a bull-head rail can be taken out by simply 

 driving out the wooden keys, and a new rail inserted without in 

 any way disturbing the chairs or spikes. To change a flange 

 rail necessitates the slackening and removal of a large number of 

 the spikes and crab bolts. 



As the sleepers under the chair road suffer less from the 

 crushing of the timber, they have a much longer life in the line, 

 and remain serviceable until they are incapacitated from decay. 

 This is a very important item in places where timber sleepers 

 are expensive. The steadiness of the chair prolongs the efficiency 

 of the spikes. 



As the actual wearing portion of the rail is the head, or wheel 

 contact surface, a liberal area consistent with the expected 

 traffic must be given to that part, whether for a bull-head rail 

 or a flange rail. By comparing the two sections, Figs. 273 and 

 274, the one for an 85-lb. bull-head rail, and the other for a 

 100-lb. flange rail, it will be seen from the dotted lines that 

 the heads of each rail are almost identical, the difference of 

 15 Ibs. being disposed of in the flange of the heavier rail. 

 Practically, therefore, we have 15 Ibs. per yard extra weight 

 of steel in the rail, on the one hand, as against the cast-iron 

 chairs and steadier permanent way on the other. 



For lines where the traffic is small, weights light, speeds low, 

 and economy of construction imperative, the flange-rail perma- 

 nent way will be very suitable. 



The writer has had long mileages of each description of 

 permanent way under his charge, both at home and abroad, for 

 many years, and the result of his experience has shown that, 

 although a fairly good road may be made with flange rails, still, 

 for constant, heavy, fast traffic, the bull-head rail with cast-iron 

 chairs makes a much stronger, more durable, and better perma- 

 nent way than any flange railroad. 



