would, thereby causing it to slip; the portion (c) would travel a less distance than it otherwise would, thereby causing it also to slip.

The above is based on the supposition that the car would move a distance equal to the circumference of the wheel at the point (b) in one revolution of the wheel. But this waste of power due to slipping is very slight, for, considering the co-efficient of friction as .15, we find that for a ton mile the energy lost by this slipping is .0104 H. P.; so small, in fact, that, on account of other advantages, it may be ignored.

The experience of the Chicago City Railway Company, which first tried this form of head, has been that it saved wear of both rails and wheels, increasing their life by about thirty-five per cent. Why not, in building a track, put in rails which are beveled to conform to the shape of the car wheel at the first, and not spend time and money wearing the wheel and rail down to fit each other?

FIG. 5.

Fig. 5 shows a section of a new and old car wheel which illustrates clearly the manner in which the tread of the wheel will wear if used on a rail with no bevel. The record of car mileage of this wheel is not known, but no doubt a great amount of energy was lost before it had worn down to its most economical state.

Fig.

FIG. 6.

shows a rail taken from the State Street track after eight years' wear, during which time 8,000,000 car wheels passed over it.

FIG. 7.

Fig. 7 shows a rail when taken out after eleven years' wear. The rail should have been taken out three years previous, but owing to impossi

bility of getting rails at the time, and the World's Fair occurring at that time, the track was not rebuilt. The true rate of wear cannot be found, as the flange of the wheel had begun to run on the flange of the rail long before it was taken out. The dotted lines show an interesting state of affairs. This section shows the wear due almost entirely to wagon traffic.

FIG. 8.

Fig. 8 shows the rail used at the present time in our 7 inch construction with chairs or tie plates. The rail weighs 83 pounds and has a head 1 inches high, beveled as described.

Fig. 9 shows the rail used at the present time in our 9-inch electric construction, without chairs or tie plates. The rail weighs 90 pounds and also has a head 1,3 inches high, beveled as described.

The question concerning the composition of the rails is one here to be considered also. How does the composition affect the life of the rail? The number of starts and stops made by cars on electric railways are enormous as compared with those on a steam road. The result is the wheels slide, sometimes spin, and this, together with the sand and dirt on the track, is a cause of great wear on both the wheels and rails. This wear, together with that due to other causes, might be greatly reduced by proper composition of metal.

I give below a table gathered from different sources showing the composition of metal advocated by experts to-day :

It would seem that the harder a rail becomes through its composition and the process of rolling, the longer it would wear. As regards this, Mr. A. J. Moxham, of The Johnson Company, says: "There are two schools-First, those who advocate a low hardened and ductile material as being of the greatest wear. Second, those who advocate the greatest possible hardness, regardless of brittleness. For many years, without taking positive grounds, I have leaned to the former class; but the experiments so far made have demonstrated to me that neither class is correct-that the correct solution lies between the two."

I come now to what has been heretofore the weakest part of track construction, namely, the joints. Once weakened, they rapidly grow worse; and not only are the rails worn at such joints, but the rate of wear of the car equipment is greatly increased. Were it only possible to get rails in continuous lengths, just as one gets trolley wire, the railway manager would be happy; but as it is we must do our best to overcome the difficulty found in making rail joints solid and rigid to withstand the severe strains which come upon them. What we want is some method of keeping the rails from pulling apart at the joints, due to contraction and spreading outward at the joints, and the shape, due to the outward