Indeed, the design is so complete, as to adapt itself, with slight alterations, to many situations and purposes.
The improvements effected on the Penryhn railway before mentioned naturally led to ameliorations in the structure of similar works elsewhere, which was especially observable on the banks of the Tyne and Wear. The expense of the transit of coals forms so considerable a proportion of their money cost, that the owners are always alive to any decided saving that may be effected therein. In the engravings above, Fig. 1 represents a side view, Fig. 2 a plan, and Fig. 3 a cross-section of a cast-iron edge-rail, of the form which ha3 been extensively adopted in the districts above mentioned. The waggons run upon the rounded edge of the rail, which is smooth, and laid as evenly and regularly as possible. The length of these rails is usually three feet, with a depth of about four inches and a half in the middle, and breadth of the top two inches; but in some railways the rails are four feet long. The ends of the rails meet in a piece of cast-iron, called a chair (see Fig. 4), and the chairs are fixed to stone blocks or sleepers, with a broad base, and weighing from one and a half to two hundred weight. These are firmly bedded in the ground, and adjusted to a proper plane for the road before the chairs are connected to them.
The goodness of the road of course depends much on fixing the sleepers in a sound, firm manner. In Fig. 1 the side view of the rail C is shown, supported at the extremities A B by cast-iron chairs E E, which rest on the stone blocks, or sleepers, D D. Fig. 2, the plan, shows the scarf joints, where the ends of the rails meet in the iron chairs E E. Fig. 3, the cross section of the rail taken at C, in Fig. 1, which is the middle of its length. Fig. 4 is a cross section at B, through the joint chair and supporting blocks.
Up to this period in the history of railways, it does not appear that any other power of draught or propulsion was employed but that of horses, except, occasionally, of fixed engines at inclined planes.
In the year 1811, a patent was taken out by Mr John Blenkinsop, coal viewer, of Middleton, in Yorkshire, for "certain mechanical means by winch the conveyance of coals, minerals, and other articles is facilitated, and the expense attending the same rendered less than heretofore." The specification of this patent informs us that it consists of the application of a rack or toothed rail, laid down on one side of the roadway from end to end. Into this rack a toothed wheel is worked by the steam-engine; the revolution of which wheel produces the necessary motion, without being liable to slip in descending a steep inclined plane.
The accompanying figure will convey to our readers an idea of Mr. Blenkinsop s plan. The boiler x is placed on a wooden or cast iron frame y- Through its interior passes a wrought-iron tube, of sufficient diameter to hold the fire and grate; this tube is carried out at the farther end of the boiler, when it is bent upwards, and continued sufficiently high to form the chimney z. a a are two working cylinders fixed in the boiler, and which work in the usual way; the piston rods are connected by cross heads to the connecting rods b b. These connecting rods are brought down on each side of the boiler, and there joined to the cranks c c, (there being corresponding cranks on the other side of the machine,) which are placed at right angles to each other; consequently the two cranks on the first shaft are horizontal, and at their greatest power, at the time the other two are passing the centre. Upon these shafts are fixed (under the boiler) two small toothed wheels, which give motion to a larger toothed wheel fixed upon an intermediate axis. A toothed wheelfis firmly keyed to the end of the same and revolves with the intermediate wheel. The teeth of/correspond with, and work into a rack R R, stretched along one side of the railway.
Motion, therefore, is given by the pistons to the wheels d d, which they communicate to the cog-wheelf; a progressive movement being given to the carriage by the teeth offtaking hold of the rack.
The communication of the pressure of the steam upon the piston through the connecting rod and cranks, it is said, produced great noise, and in some parts of the stroke great jerks, each cylinder alternately propelling or becoming propelled by the other, as the pressure of the one upon the wheels become greater or less than the pressure of the other; and when the teeth became worn, they produced a rattling noise. Mr. Galloway states that several of these engines were constantly employed in drawing coal-waggons between Middleton Colliery and Leeds; and with reference to their effectiveness, the following particulars were given by Mr. Blenkinsop in reply to queries put to him by Sir John Sinclair. He stated that his patent locomotive engine, with two eight-inch cylinders, weighs five tons; consumes two-thirds of a hundred weight of coals, and fifty gallons of water per hour; draws twenty-seven waggons, weighing ninety-four tons, on a dead level, at three and a half miles per hour; or fifteen tons up an ascent of two inches in the yard; when lightly "loaded" it travels ten miles an hour, does the work of sixteen horses in twelve hours, and costs 400l.
In the following year, 1812, Messrs. William Chapman, of Durham, and E. W. Chapman, of Wallsend, Northumberland, took out a patent for "a method or methods of facilitating the means, and reducing the expense of carriage on railways and other roads;" which they describe as chiefly consisting in the use of a chain, or other flexible and continuous substance stretched along the road to be travelled, properly secured at each end, and at suitable intervals; and in the application of this chain round, or partially round a grooved barrel or wheel, in such manner as not to slip when this grooved wheel, which is fixed upon, before, or behind a carriage containing the motive power, shall be put in. motion by that power, so that by the revolution of the grooved barrel round its axis, either one way or the other, it shall necessarily draw the said carriage, and any others which may be attached to it, within its power of action. As the carriage containing the motive power, when thus loaded, may be too heavy in some instances for the existing iron or wooden rails, if it rested on four wheels only, Messrs. Chapman proposed to use six or eight wheels, in order that they might more freely move round curves in the road, and that the weight might be more distributed thereon; the pressure being thus reduced upon each bearing point, in the inverse proportion of the number of wheels.