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. [Illustration: Fig. 273, 274] Briefly summarized, the principal advantages and disadvantages of the 199 two kinds of rails stand as follows:-- ADVANTAGES. Bull-head Rail. Flange Rail. Large bearing surface of chair Fewness of parts, and less upon the sleeper, and greater cost. stability of the rail. Smaller quantity of ballast Longer life of wooden sleeper. required to cover up the foot of rail. Impossibility of rail tilting over outwards. More lateral stiffness than the bull-head rail. 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. DISADVANTAGES. Bull-head Rail. Flange Rail. Bull-head Rail. The small rail-seat area on sleeper throws great crushing Greater cost. weight on the timber. More ballast required to cover Shorter life of wooden up the rail. sleepers from the cutting down of rail-seats. Less lateral stiffness than the flange rail. 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 consequence of greater tendency of the fastenings to work loose. Difficulty in getting flange rails straightened laterally.