The improved practice is not only to dispense with the lower vertical flange under the head of the rail, but to extend the base of this part of the rail, thus (Fig. 6). This rail weighs about 50 lb. per lineal yard, and is used for heavy traffic.

Where there is less traffic, the section (Fig. 7) has sometimes been used. This weighs from 28 lb. to 30 lb. per lineal yard.

In European cities, and especially in London, there are more private carriages, cabs, omnibuses, and light vehicles of various kinds, than in America. It is therefore more necessary to adopt a form of rail which offers little obstruction to the general road traffic. In the interests of the tramway proprietors, it is doubtless better not to have grooved rails; but in London and other European cities it is considered that in the interests of the public generally it is better to use them, because they do not project above the surface of the roadway or track, and therefore offer little or no obstruction to vehicles passing over in any direction.

It will thus be seen that in designing the permanent way and track of a tramway about to be laid no fixed rule can be followed; but that the engineer must carefully inform himself of the nature of the road along which it is to be laid, and above all, of the probable number and class of carts, waggons, and other

public and private vehicles likely to pass along the tramway route.

Our own opinion is that in European and other cities, where there are many public and private vehicles, grooved rails should be adopted; but the head of the rails, or that part on which the car-wheels run, should have an extra thickness of metal to allow for the great wear and tear; or, better still, these rails should be made of steel. For as the head of the rail is worn away the groove becomes shallower, the flanges of the wheels are then more worn, and very slight obstructions are sufficient to send the car off the line.

Sleepers.-When the form of rail to be used has been decided on, the next thing to consider is on what the rail shall be bedded, and how it shall be fastened. These are two very important considerations; for if the rails become loosened the gauge cannot be preserved, and the wear and tear of the cars and permanent way is seriously increased.

In the first place, it should be remembered that the permanent way of a tramway has to be considered very differently from that of an ordinary railway. In the latter, elasticity in the sleepers is an advantage, as it lessens the shock of heavy passing loads running at high speed, while at the same time these sleepers are laid in loose ballast, are well drained, easily accessible, and can at any time be packed up to their proper level. For tramways, it appears to us worse than useless to provide an elastic bed for the rails; for when the

bed of the rails is elastic, and that of the contiguous paving is inelastic, there is an unequal settlement of these two important parts. In this way the surface of the roadway becomes uneven, and ruts are formed near the rails, to the detriment of vehicles of all kinds.

It should also be borne in mind that tramways are generally laid in public roads, and are usually paved on each side of the rails, so that the whole of the sleepers and all but the surface of the rails are buried, and it is impossible to pack them up or alter their level without first removing the adjoining paving. It is therefore additionally necessary to make them of durable material, and to bed them thoroughly well in the first instance, in order to avoid the expense and general nuisance of opening up the paving.

Timber has hitherto been generally adopted for tramway sleepers, but it not only decays rapidly and requires to be often renewed, but owing to its yielding nature, and to the fact of the sleepers being frequently deflected by passing loads, the fastenings of the rails work loose, and the difficulty of securing them is much increased.

The superintendent of one of the chief tramways in New York City, a very competent authority on the subject of tramways in America, has given it as his opinion that "from long experience he is quite convinced that a perfect track for horse cars should be as solid as possible, and not like a steam railroad; for with the small weight of the horse car and the slow speed an elastic track sooner wears away, and gives too much

spring to the car." He considers that "a light rail carried on continuous iron sleepers will last much longer, and save much in car repairs."

Various systems of iron permanent way have recently been invented, and this is doubtless a step in the right direction, although opinions differ somewhat as to the actual results achieved.

Nearly all the iron systems which have been tried consist of rails supported on iron blocks or chairs placed at intervals, the rails being specially rolled with vertical webs to prevent deflection between the supports. Hitherto the first cost of the iron systems has exceeded those in which timber sleepers are used. Among other objections, it has also been found in practice that when the rails are carried on a series of fixed points, a jolt or shock is given to the car as it rides over the supports. This is injurious to the cars, and tends to loosen the permanent way.

To meet the objections urged against the different systems hitherto tried, we have designed an iron permanent way with continuous cast-iron bearers for the rails, to take the place of the usual longitudinal timber sleepers. The bearers are also provided with a simple contrivance by which the rails are securely held in place. The cast-iron bearers are made in lengths of about 3 feet, and are fastened together so as to form a practically continuous longitudinal sleeper for the rails. Sufficient play is allowed in the joints to admit of the bearers being laid on the sharpest curves in use, so that no special castings are required. The rail is made

with a fillet on each side, projecting downwards: these fillets are slightly inclined inwards, and the ends of the

bearers are similarly inclined and overlap, so that a wedge can be inserted between them, and when the rail is seated on the bearers like a saddle and the wedge is tightened, not only are the bearers fastened transversely, but owing to the inclined surfaces the rail is drawn down vertically on to its permanent bed, and the whole is thus very firmly secured. The width of the bottom flange of the bearers can be made equal to that of ordinary timber sleepers, but in practice the dimensions of the castings should depend on the nature of the foundation and the traffic likely to pass over the line. There are no projections whatever beyond the sides of the rails, so that the paving can be laid in an even line, close to the rails.

This design is considerably cheaper than any with timber sleepers, and in fact we believe it is the cheapest of all timber or iron systems in use.