cement concrete of an average width of 15 inches and a depth of 9 inches. At the joints the rails rested upon a steel plate 3" x 6" x 24", bedded on a concrete beam. The concrete of the beam was formed of one part of Portland cement, two and onehalf parts of sand, and five parts of broken stone. On curves and in special work, instead of the concrete beam, oak ties were used bedded in 6 inches of concrete similar to that above described. After the subgrade had been prepared the rails were placed in position, the track made up, surfaced, lined, and gauged, resting on wooden blocks placed under each rail every 8 or 10 feet. The contractor then excavated under the rails and placed in position the wooden forms of the beams.

The concrete for the foundation of the pavement was then laid between the rails, being thoroughly tamped up under the ties so as to fill the corrugations. After this concrete had received one day's set, the wooden forms were removed and the concrete beam placed in the trench which was left for it, and thoroughly tamped up under the rail so as to cover the rail-flange. The concrete in the beams was allowed to set for eight days before the track was used.

During these eight days the track was naturally exposed to changes of temperature, and as it was laid during extremely hot weather, the temperature changes were extreme between day and night. The amount of expansion and contraction was found to be from 3 to 4 inches in 400 feet. In order to protect the track from these changes in temperature, the rails were covered with V-shaped troughs made from boards 12 inches wide and 7 feet 6 inches long, so that the trough could be set between the tie-rods.

In a brick pavement where sand was to be used on the foundation, the rails were covered with sand previous to placing the troughs over them. In the asphalt pavement the troughs were used until the beam was put in, when the toothing-blocks were laid as fast as the beam was constructed, affording the same protection from temperature as did the sand on the brick streets. This device successfully prevented any trouble from expansion.

On the brick streets on the outside of the rails the brick was laid up close to the head of the rail, the space between the two flanges of the rail being filled with cement mortar, but on the

inside special brick were provided, made of such shape that they would extend under the head and butt up tightly against the flange. On the asphalt streets toothing-blocks were laid alternately as headers and stretchers, the space between the flange being filled as before. On the inside, however, the blocks were brought to within 14 inches of the head of the rail, and the space between the block and flange to within 14 inches of the top, being filled with cement mortar, and the space above this cement mortar being filled with specially prepared asphaltic cement, the street-car company running a car over the track to form a groove with the flange of a wheel. It is said that, although this track was laid in the hottest weather, none of the joints opened in the winter, and a careful examination could discover only about 30 per cent of the joints.

The above description was taken from the Street Railway Journal for August, 1898.

In March, 1900, the general manager of this road says: "We have not expended one penny in maintaining it since it was put in, and I consider it as nearly a permanent roadbed-construction as I have ever seen."

Fig. 39 shows the construction adopted by the Third Avenue

Railway Co. of New York City when it substituted electric traction for cables. It is not intended to show the entire detail of the work, but only that which would affect the pavement. It will be noticed that the rail is the regularly adopted Trilby rail set on

a wooden creosoted beam. The object of this beam is to give a certain amount of elasticity to the track, so as to make it smoother and more comfortable to passengers. The yokes were spaced 5 feet apart from centre to centre.

The above construction was used on the subsidiary lines, but on Third Avenue proper the form of the yoke was somewhat changed, and instead of the creosoted beam a heavy spring was used resting upon the yoke, and upon which the rail rested. This spring is so designed that when the centre is depressed the ends rise, presenting a corrugated surface of such strength that it is estimated that it will sustain a weight of from 10,000 to 12,000 pounds. The springs are 4 inches wide, and the deflection at the passage of a loaded car carrying about 6400 pounds on each wheel is about of an inch and is noticeable from the street.

From a pavement standpoint it would seem that a wood construction would be better than the spring, especially if laid in an asphalt pavement, as a real deflection of of an inch would break the joint between the asphalt and the rail enough to permit the entrance of moisture, which would naturally lead to disintegration. In Third Avenue, however, the pavement outside of the track is granite block, but, the space between the conduitslot and the rail being so narrow, it was deemed best to pave this with asphalt. Concrete was laid to within 2 inches of the top of the rail, when about 1 inch of asphalt pavement was spread over the surface in which was bedded a specially designed grillwork of 3-inch cast-iron bars, forming squares about 3 inches in size. More asphalt was then filled in on top of that first laid, in and around the iron, and thoroughly rolled and compacted so that its finished surface was in a straight line between the slot and the head of the rail.

Fig. 40 represents the permanent construction of railwaytracks in an asphalt street in Detroit, Mich. This shows the space between the tracks and rails paved with brick or stone blocks. The special part of this construction is the tie-bar which is bolted to the base of the rail, there being no connection at all between the webs as in the other methods heretofore shown. The Detroit Railway Co. consider that this method of construction is While the tie connecting the webs of the rail is not

a success.

particularly objectionable in an asphalt pavement, as the concrete is filled all around it, it is decidedly so in a stone block pavement. It often happens that the ties are not exactly square with the

track, and, in any event, it makes it necessary to use a certain number of courses of blocks between the ties, which often makes the joints wider than is desired.

Fig. 41 shows the tie-construction in an asphalt pavement in Cincinnati, O. This city was one of the first cities to adopt con

crete construction, and, as is shown in the cut, lays concrete under all the ties and, in the case of asphalt, over them as well, so that the tie is entirely surrounded with concrete. Very satisfactory results have been obtained from this kind of construction.

In the city of Rochester, N. Y., when a street is permanently paved the city orders the street-car company to construct a per