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 lbs. being disposed of in the flange of the heavier rail. Practically, therefore, we have 15 lbs. 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 permanent 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 permanent way than any flange railroad.
Briefly summarized, the principal advantages and disadvantages of the two kinds of rails stand as follows:—
| ADVANTAGES. | |
| Bull-head Rail. | Flange Rail. |
Large bearing surface of chairupon the sleeper, and greaterstability of the rail. Longer life of wooden sleeper. Impossibility of rail tiltingover outwards. Facility for changing a railwithout disturbing thefastenings in the sleepers. Easier to maintain, owing toless disturbing strains on thefastenings. A bull-head rail is morereadily set or laid to followline of curve. In most cases the one set ofchairs will serve for a secondset of rails. Perfect straightness of rail:it is very rare to find acrooked bull-head rail. Easier to roll, and morelikely to obtain uniformity ofsteel. | Fewness of parts, and lesscost. Smaller quantity of ballastrequired to cover up the footof rail. More lateral stiffness thanthe bull-head rail. |
| DISADVANTAGES. | |
| Bull-head Rail. | Flange Rail. |
Greater cost. More ballast required to coverup the rail. Less lateral stiffness thanthe flange rail. | The small rail-seat area onsleeper throws great crushingweight on the timber. Shorter life of woodensleepers from the cutting downof rail-seats. The edge of flange cuts thespikes after a few years. The undulation of the railunder trains tends to raisethe spikes, and causes lateralmovement in the rails. More difficult to maintain, inconsequence of greatertendency of the fastenings towork loose. Difficulty in getting flangerails straightened laterally. More difficult to set tofollow regular line of curves. More difficult to roll, andless likely to obtainuniformity 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 accommodation, 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
a position so thoroughly appreciated by the public that any check on their reasonable use or extension would be considered as detrimental to the interests of the travelling community.
As a rule, these tramways are laid down on streets or roads previously constructed for the ordinary road traffic, where all the preliminary work of earth filling, bridges, drainage, etc., has already been accomplished, and there only remains the selection and laying down of the rails or permanent way over which the tram-cars will have to run. The description and weight of permanent way to be adopted will depend largely upon the weight of the cars to be used and the system of motive-power decided upon for the haulage—whether horses, steam, cable, or electricity.