Fig. 5. A plan, in which the axle H is shown with two arms KK at right angles to H, which are made to act as pivots to the wheels, when intended to be moved in a direction at right angles to the bars.

Fig. 6. Is a view of the same parts described in fig. 5. The wheels marked W, in all the figures, are of cast iron, and cost three shillings and sixpence each.

No. 72.

Account of an Improvement in Tram Plates for Carriages on Rail Roads. By Mr. CHARLES LE CAAN.* (With an engraving.)

SIR-I have forwardad to the Society of Arts, &c. a specimen of my new method of laying rails, or tramplates, on such a plan as has met the entire approbation of those who have seen it, and are acquainted with the principle on which such roads should be formed. Rail roads are daily increasing, from the great advantage they afford to manufactories connected with mines and, minerals, and particularly to collieries. They also promote agriculture, by occasioning lime to be procured from places almost inaccessible by any other means, or whence it could be otherwise brought on moderate terms.

I flatter myself, that every improvement on this system will be of national importance. The honour I received last year from the Society of Arts, &c. has stimulated me to submit the present subject to their consideration.

I have also sent a drawing of my method of laying the tram-plates, with an estimate of the saving that will arise

⚫ Nicholson, vol. 22, p. 339. From the Transactions of the Society for the Encouragement of Arts, &c. vol. 25, p. 87.--Twenty guineas were voted to Mr. Le Caan for this improvement.

to the public, by adopting the said method, with necessary remarks on the principle on which it is founded. The leading rail or tram-plate has neither tenon nor mortice over the plug. The stop-plate terminates the specimen, which stop-plate should go in with some degree of tightness when laid for actual use, but in the present case that force is not necessary, as the wooden blocks, by a carriage of upwards of two hundred miles, may in some small degree be misplaced. I hope any impediment of that nature will be rectified or allowed for. I wish it to be understood, that a stop-rail is intended to be placed at every thirty yards, at which distance any repairs may be made within ten minutes, which by the present mode frequently occupies more than twice that time, exclusive of disturbing in some measure the line of road. By my method, the plates have a certain degree of play, which is absolutely necessary to avoid that breakage, which too frequently takes place when they are fixed with nails and plugs.

The plates which I send have been fixed in stone blocks, and are nearly as rough as when taken from the sand. If I am favoured with any mark of the society's approbation, I shall hold myself bound to transmit such farther communications on this subject as may be required by them, or any person desirous of adopting my plan. I am, &c.

CHARLES LE CAAN.

Llanelly, Carmarthenshire, May 12, 1806.

SIR-I have considered the improvement made by you in the specimen exhibited of a new design of a tram-plate, and am of opinion, that much advantage may be derived to tram roads by the adoption of your plan, in preventing the temptation of stealing the wrought iron nails, with VOL. II.

which the plates are usually fastened, and by facilitating the operation of laying down new tram roads, and repairing of old ones. I am, &c.

To Mr. LE CAAN.

Llangennech Park, April 2, 1806.

J. VANCOUVER.

SIR-Several tram-plates on your new method of fixing without either nail or plug have been cast under my immediate inspection, at Stradey furnace. The same may be made with as much ease as any others now in use, and I conceive they will obviate the many impediments that arise from the irregularity of driving the nails. I have no doubt from my observation of yours, but that they will answer extremely well, and prove less expensive. I am, &c.

To Mr. LE CAAN.

Stradey Furnace, April 18, 1806.

J. LEWIS.

CERTIFICATES were also received from Mr. R. Jones of Swansea, agent to general Ward's colliery; from Mr. James Barnes, who formed the Myther and Carmarthenshire rail road; and Mr. Edward Martin, of Morristen, an eminent colliery, surveyor and planner of rail roads, all testifying the advantage of Mr. Le Caan's invention.

Reference to the Engraving. Plate 11, Fig. 7, 8, 9, 10.

THE tram-plates, fig. 7 and 8, are fastened by means of a tenon and mortice AB, each having a correspondent bevel, just sufficient to keep the end from rising up, so that the head of one plate confines the end of the other;

by this means, the workmen are obliged to form their road in right lines, and maintain perfect levels, as the mortice and tenon confines them to the required exactness necessary to make a perfect road: curves or any given segment may be formed with the same nicety, by having two bevel rails or plates made for such purposes.

Fig. 8, A side view or longitudinal section of the two plates placed on their stone blocks or sleepers CD, shows two plugs in dotted lines, one bevel, the other perpendicular, cast in the stop-rail or plate, which is so called as it prevents the others from moving, and when taken up releases all those between the stop-plates; twenty-five yards of rail roads made with these plates, may be taken up and replaced within ten minutes. The plugs in dotted lines are shown in their proper positions within the sleepers EFG.

The usual length of a tram-plate is three feet, the flanch or outside edge H, about one inch and half high, the sole or bed I, from three inches and a half to four inches broad, and three fourths of an inch thick; but these dimensions may be varied according to circumstances. The most approved weight has been fourteen pounds to the foot, or forty-two pounds to the plate, the ends from which the plugs project, and to which the tenons and mortices fasten, should be one fourth of an inch thicker than the other part of the plate.

Fig. 9. AB show the under part of the tenon and mortice, and the form of one of the sloping or bevel plugs.

The diameter of the plug near the shoulder is one inch and three quarters, reducing to one inch, its length two inches and a half, forming an angle of eight degrees, the plate from which it projects is counter sunk, so that the shoulder of the plug may not receive any sharp pressure or prevent the plate from having a perfect bearing.

There is a small groove in the whole length of the exterior of each plug, to admit a wire to pass to its extremity, to draw the plug out if broken by any accident, also to admit the expansion of water, in case of severe frost.

The blocks or sleepers, EFG, on which the tram-plates are placed, should by no means be less than one hundred and twenty pounds each in weight, but should be heavier on some kinds of ground: the depth of the hole for the plug should be three inches, and worked according to the inclination of the plug, for which purpose the stone-mason should have a standard cast-iron guage; there should be projections, K, cast with the flanch or outside edge of the tram-plate, as shown at fig. 7, to make the plates lie firm on their sleepers.

Fig. 10, is a section of one of the ends of a tram-plate, in which H shows the flanch or upright edge, I the flat part or sole on which the wheels of the waggons run, D one of the plugs, K the projection behind the flanch to make the plate lie firm on the blocks.

GENERAL OBSERVATIONS.

THE advantages of laying plates on the above principle are obvious; the blocks being put in their places never sink below their intended level, the act of driving either nail or plug, (which requires a considerable degree of force, and too frequently destroys the level of the road,) being here unnecessary. In the common mode of making rail-roads, from the irregularity of nails, particularly in forming their heads, few can be driven exactly even with the plate, and they are perpetually obstructing the passage of the waggon; the workmen frequently not proportioning their holes and plugs to the hole in the block also occasions considerable breakage; the exertion necessary to fix a rail or plate completely is great, and