When comparing the relative merits of the flange-rail and bull-head-rail permanent way, the question of strength and durability must be considered, as well as that of economy. The flange-rail road has undoubtedly fewer parts and fastenings, and when the flange is wide, the sleepers sound, and the rail securely held down to the sleepers, the result is a smooth running road. So long as the rail can be maintained in a constant close contact with the wooden sleeper, the running is almost noiseless, the jarring on the rails being absorbed or taken off by the timber; but so soon as a little space or play takes place between the spikes or other fastenings and the upper surface of the flange, the rail obtains a certain amount of rise, or lift, which comes into action upon the passing of every rolling load, producing unsteadiness in the rail and a clattering noise in the running. A flange of 5 inches, on a sleeper 10 inches wide, has a bearing surface of 50 square inches (assuming the sleeper to be square cut, without any wane on the edges), and this area of 50 inches is only about half of the bearing surface on the sleeper of an ordinary modern cast-iron chair. Main-line locomotives have weights on the driving-wheels varying from 16 to 18 and 20 tons. Taking 18 tons as representing a common practice for a large express engine, would give 9 tons as the weight imposed on 196 each rail by each driving-wheel Assuming this weight to be distributed over three sleepers would give a dead weight of 3 tons per sleeper, or 134 lbs. on every square inch of the 50 square inches of surface, or rail-bearing area, on each sleeper, without taking into account the effect of the blow or percussion from the rolling load. The presence of a loose sleeper throws additional weight on the adjoining sleepers, and increases the destructive influence on the timber. The constant application of heavy rolling loads on a small bearing area of timber crushes and wears away the timber very rapidly. The small bearing surface of the flange rail expedites the cutting down into the sleeper, and as the rail beds itself further and further into the wood, the fastenings must be driven or screwed down to follow the flange. Spikes may be driven down, but the further they go they have a less thickness of timber for a bed, and therefore a diminished hold. Crab bolts are apt to become rusted or ironbound, so that they cannot be screwed further, and must then be taken out and replaced with new ones. The narrower the flange, the more rapidly does the rail-seat cut down to a thickness inconsistent with safety. The sharp edge of the flange-rail has a tendency to cut a channel in the spike, and it is not at all an unusual occurrence to find strong square shanked dog-spikes, which have been thus cut into to the extent of a third or even half their thickness. The comparative narrow flange places the spikes at great disadvantage in point of leverage for holding down,