Tramroads are much esteemed in Wales; and in consequence of using them, it is found desirable to divide the pressure upon the rails as much as possible; hence, small carriages are used, and these lead to small wheels, so that the effect of a given power is not above half what it ought to be ; and yet the enormous increase of railroads in Wales renders it evident that some benefit is received from adopting this system of conveyance. In 1791, there was scarcely a single railway in South Wales; and in 1811, the complete railroads connected with canals, collieries, &c. in Monmouthshire, Glamorganshire, and Caermarthen shire, amounted to nearly 150 miles in length, exclusive of underground ones, of which one company in Merthyr Tydvil possessed about thirty miles ; since which period the lines have been extended to, at the least, three hundred miles.
Whenever it is found necessary for railways to cross any public road, the space between the rails must be paved or firmly causewayed to the level of the top of the flinches, in order that carriages passing along the road may be enabled to pass cleat over the rails. It is also absolutely necessary, in single railways, to have certain places formed at intervals, where the empty carriages, in returning may of the road, in order to allow the loaded ones to pass,: a place of this description is termed a turn-out. The waggons are easily directed into it by a movable rail, termed a pointer, fixed at the intersection between the principal rail and the turn-out, and turning on its extremity so as to open the way into the turn-out, and shut that along the road ; and whenever one line of railway happens to cross another, this contrivance is also adopted.
The origin of edge-rails cannot easily be traced. The wooden rails partook of this character; for they were generally rounded a little on their upper sur faces, and flanges were put upon the peripheries of the wheels, which, projecting downwards over the sides of the rails, kept the wheels in their tracks ; and in some cases, square wrought-iron bars were fastened over the wooden rails, partly with a view to strengthen them, as well as to form guides to the wheels : the transition to improved forms was therefore easy. In 1789, Mr. Jessop introduced a cast-iron edge-rail in the public road at Loughborough, the upper surface of which was flat, and the under of an elliptical shape.
It was not, we believe, until the beginning of the present century that edge rails were much known; as it appears that Mr. Benjamin Wyatt, of Lime Grove, near Bangor, imagined himself to have originated them. This gentle man's invention, as applied to the Penrhyn Slate Works, is thus described by himself in a letter to the editor of the Repertory of Arta, and is inserted in the third volume of the second series of that valuable work. In allusion to the peculiar rails then in use, he says—" The rail hitherto made use of in most rail ways is a flat one, three feet in length, with a rib on one edge, to give it strength, and to prevent the wheels, which have a flat rim, from running of Observing that these rails were frequently obstructed by stones and dirt lodging upon them; that they were obliged to be fastened to single stones or blocks on account of their not rising sufficiently above the sills, to admit of gravelling the horse path; that ;the sharp rib standing up was dangerous for the horses; that the strength of the rail was applied the wrong way; and that less surface would produce less friction ; led me to consider if some better form of rail could not be applied. The oval 'presented itself as the best adapted to cor rect all the faults of the flat rail, and I have the satisfaction to say, that it has 'completely answered the purpose in a railway lately exe cuted for Lord Penryhn, for his lordship's slate quarries in Caer marthenshire, to Port Penryhn, the place of shipping. The wheel
made use of on this rail has a con cave rim, so contrived in its form, and the wheels so fixed upon their axes, as to move with the greatest facility on the sharpest curves that can be required." It is obvious by the annexed section, which re presents the rail, a, of its full and exact1tize, that no dirt can lodge upon it, and that it must be very strong for its weight ; and is calculated to resist both the per pendicular and lateral pressure. That it must occasion but little friction, that it may be placed upon the sills to admit a sufficient quantity of gravel to cover them, and present no danger to the horse, they were cast 4 feet 6 inches long, and weighed 36 lbs. each. The lower part b is cast to each end of the rail, three inches long, to let into the sills, which have a dovetailed notch to receive them.
The Penryhn railway is six miles and a quarter in length, divided into five stages. It has three-eighths of an inch fall in a yard, with three inclines ; was begun in October 1800, and finished in July 1801. The annexed sketch shows the kind of waggons that were used on this railway, twenty-four of which con taining 24 tons, were drawn by two horsesSone stage) six times a day,; which is 144 tons per day, drawn 6i miles per day. This quantity of work was pie viously performed by 144 carts, and 400 horses ; so that fen horses will by means of this railway do the work of four hundred! It has been repeatedly proposed of late years, to form a rail, or iron way, upon a portion of the common public road, so as not to rise above the level of the general surface, and thus Tamil carriages to cross them in any direction, without impediment. The utility of the principle of this arrangement has for some time past been demonstrated by the excellent granite stone-way for waggons, in the Commercial Road, and the adoption of the same plan in Friday-street, and other parts of London ; for by these rough structures, the effect of horse-power is at the least doubled, or one horse is saved out of every two. If so much has been gained by so slight an improvement of the surflice; what may not be expected when ignorance and prejudice shall permit the intro duction of such perfect surfaces as iron will afford? There is, however, no need of conjecture in the matter; the results of the actual work upon the Manchester and Liverpool Railway show us, that a force of draught equal to a weight of one pound descending from a pulley, is capable of drawing 200 lbs. upon the rail at 2e miles per hour, which is the ordinary pace of a cart horse, whose power of draught through a day's work is estimated at 150 lbs. drawn up over a pulley at the same velocity. Consequently, we have 150 X 200=30,000 lbs.; or between 13 and 14 tone, drawn by one horse with perfect ease! Whatever admiration such effects might excite in the public mind, they would create no surprise to persons at all acquainted with mechanical science ; indeed, it appears from experiments made by Mr. Wood, with a well constructed model, that the whole of the resistances to the motion of a carriage upon a level railway are capable of being reduced to the five hundredth part of the weight ; conse quently one horse would be competent to draw (500 X 150=) 75,000 lbs., or upwards of 33 tons I But it is not to be expected that the accuracy of work manship in a model could be carried into effect, or the expense of it afforded on the great scale ; nevertheless, when the numerous little progressive amelio rations which the present extensive practice of our railroad mechanics are daily developing, are taken into account, it scarcely admits of a doubt that a horse may be rendered capable of drawing, at the least, 20 tons.