Engineers and Mechanics Encyclopedia 1839: Railways: Charles Le Caan
In many of the railroads where horse-power is employed to draw the carriages, the animal is frequently required to check the velocity of the waggons, so that they may not exceed a certain degree of motion; and when a horse is pressed beyond his power of resistance, he necessarily quickens his pace; if, under these circumstances, he makes a trip, he is almost store to fall, and then to suffer severe, if not fatal injury, by being forced down the declivity. To prevent such serious accidents, Charles Le Caan, of Llanelly, in Caermarthenshire, about thirty years ago, constructed a brake of great simplicity, which cannot fail of checking or stopping the carriages under such circumstances, and is therefore deserving of more public notice than it has hitherto received.
In the following engraving see have shown the application of slots contrivance to a common Welch cart used upon rails. a represents the brake, which we have shown as made of iron, it being in the original a very clumsy mass of wood, shod with iron; the slime or skid ought to be somewhat broader than the tire of the wheels; the top of the brake turns upon a pivot at b, and the lower part is connected by a strong chain c to the shaft d. The shafts are jointed at e to the frame of the cart or waggon; and when the horse is upon his legs, the shaft-chain and brake are in the several positions shown by the dotted lines at f-g-h, the latter, which represents the brake, being then quite clear of the wheels as well as the rails; but when the horse falls the shaft takes the inclined position shown at d, and the skid of the brake a, by its weight, is thrown under the wheel, which it takes off the rail; the rolling motion is thus changed into a sliding one, and the great friction thus induced either stops the descent of the carriage, or retards it sufficiently to prevent serious injury resulting.
In a letter to the Society of Arts, in London, Mr. Le Caan observes:-
“To prevent the great trouble arising from turning a waggon round upon a railroad, it would be better to have a brake to each of the four wheels; in which case, after the waggon has discharged its load at the place of destination, the chains c may be loosened from the shafts, and fastened upon hooks so as to keep the brakes suspended over the road; the bolt at e which attaches the shafts to the body of the waggon, is then to be removed, and, with the shafts, placed in a similar manner on to the other end of the waggon, which now becomes the fore part, the horse drawing it back to be again loaded. Whenever the waggon is ascending, the checks behind the waggons may occasionally be let down and used as rests to relieve the horse when necessary.”
The mode of fastening down tram-plates by bolts or spikes was found to be attended with several inconveniences, owing to the occasional projection of their heads, their becoming loose, and hence both the plates and bolts being frequently stolen. to the entire stoppage of the traffic upon the road.
To remedy these evils, Charles Le Caan, of Llanelly, in South Wales, contrived a mode of forming the plates, to that no bolting or nailing was requisite, but each plate in succession fastened down the previous one.
Fig. 1 represents a plan of the junction of two plates, placed on a stone sleeper D.
Fig. 2 shows a longitudinal section of the same.
The plates are joined by a dove-tailed notch and tenon, and an oblique plug is cast on each plate, which is let into the stone sleeper; but for the advantage of taking up the plates to repair any defect, there are plates at every thirty yards, with perpendicular plugs; such plates are called stop-plates. The diameter of the plug near the shoulder is one inch and three quarters, at the point one inch, its length two inches and a half, and its obliquity, shown in Fig. 2, about eight degrees. A small groove in the whole length of the exterior of such plug is made to allow the water in the hole to expand in freezing; and it also serves to admit a wire to draw a broken plug out by it.
The holes for the plugs should be cut to the depth of three inches by a standard gauge of cast-iron, and countersunk so as to allow the end of the plate to bed firstly on the block which supports it. Fig. 3 is one of the ends of a tram-plate, in which H shows the flange or upright edge; I the flat part or sole, in which the wheels of the waggon run; D one of the plugs; and K a projection behind, to render the plates firmer upon the blocks. The usual length of one plate is three feet; the flanch H is one and a half inch high; the sole, or bed, three and a half, or four inches broad, and three-fourths of an inch thick; but these dimensions are varied according to circumstances.
The most approved weight has been forty-two pounds for each plate; the ends from which the plugs project, under which the tenons and notches are made, should be a quarter of an inch thicker than the other parts of the plate. The weight of the blocks or sleepers should not be less than about 120 pounds each; and some kinds of ground will require heavier. In this method the wheels of the waggons cannot be obstructed by the heads of the nails rising above the surface, and the blocks are not disturbed by fixing the plates; and when repairs are necessary, the plates must be formed for the purpose. When tram-plates are fixed by spikes to stone sleepers, there is some difficulty in keeping the joint even and in its place; but it seems to be successfully obviated by using a saddle-pits to receive the ends of the nails at the joints, an improvement which was introduced by Mr. Wilson on the Troon Tramroad.
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 front adopting this system of conveyance.
In 1781, there was scarcely a single railway in South Wales; and in 1811, the complete railroads connected with canals, collieries, &c. in Monmouthshire, Glamorganshire, and Caermarthenshire, amounted to nearly 150 miles in lengths, exclusive of underground ones, of which one company in Merthyr Tydfil 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 flanches, in order that carriages passing along the road may be enabled to pass clear 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 get off 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.
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