A Practical Treatise on Rail-roads, and Interior Communication in General ...

head, м N, Fig. 3, and which works the rod, P, and slide, e e, back and forwards; the two weigh-bars, 5, 6, Fig. 6, are in the position attached to, or resting upon, the cross-bars, 5 and 6, Fig. 7. As shewn at Fig. 6, these forked rods are hung at their other, or upper ends, from arms, or levers, fixed upon the centres, g and h; 11, and 22, being suspended from the lever, hh'; and 3 3, 44, from the arm, or lever, g g'. When the forked arms are thrown into geer, or rest upon the weigh-bars, RS, R м, as I 1, upon 5, and 22, upon 6, Fig. 7, and, being attached to the rods, a b, of the eccentrics, the arms, N and T, are worked by the eccentrics, and, consequently, the slides, e e', ee, of the cylinders; but, when the forked arms are lifted out from off the weigh-bars, 5 and 6, they move back and forwards, suspended from the end of the levers, as in the case of 3 3, 44, from g g', without moving the slides at all. The system of working the slides, therefore, is, that four forked arms attached to, and working continually with, the eccentric sheeves, two for each cylinder, are alternately thrown in and out of geer, as the engine moves in different directions; two only of these forked arms being in action at one time, the two which are resting upon the weigh-bars, 5, 6, or 7, 8, are working the slides of the cylinders, and the other two, which are not resting upon these bars, are inoperative. It is only, therefore, necessary, in order to change the motion of the engine, to lift one set of these forked arms, from off the weigh-bars, 5, 6, 7, 8, and replace them by the other two. We shall now describe how this is effected, gf is another arm, upon the axle, g, from which the rod, e, proceeds, to the handle, н, fixed upon the fulcrum, F, and worked by the engine-man; the lever, g g', is prolonged in the opposite direction, to i, to which a pin is fixed, fitting vertically within the

oblong hole, in the lever, hh', the prolongation of the lever, hh', from g, being shewn by the dotted lines. When, therefore, the handle, н, is thrown back, as shewn in Fig. 6, the lever, g g', is raised upwards, and, with it, the forked arms, 3 3, and 44; while, at the same time, the lever, hh', is depressed, by the pin, i, working in the oblong hole, at i, and with it the forked arms, 1 1, and 22; and, consequently, by this operation, the two forks, 11, and 22, are thrown into geer, or upon the weigh-bars, 5 and 6; while the two forks, 3 3, 44, are raised up, or lifted, out of geer, or from the weigh-bars, 7 and 8, Fig. 7.

When, however, the handle, H, is thrown forwards, the lever, gg', is depressed, and the lever, hh raised by the pin, i, acting in the same manner as before, against the oblong hole; the forked arms 1 1, and 22, are, therefore, lifted from off the weigh-bars, 5 and 6, or thrown out of geer, and the forks, 33 and 4 4, are depressed or thrown into geer upon the weigh-bars, 7 and 8, Fig. 7; N, and T, Fig. 7, representing the ends of the arms, N and T, Figs. 3 and 1; the slides are thus, by this contrivance, alternately engaged or disengaged from the two eccentrics.

The rods a, and c, are attached to the eccentrics, 1 and K, of one engine, and the rods b, and d, to the eccentrics, H, and G, of the other. The eccentrics, K, and G, being fixed in the proper position upon the axle, for applying the steam to the cylinders at the proper time, when the engine is moving in one direction; and the eccentrics, I, and н, when the motion is reversed, or when the engine is moving in the opposite direction. According to this arrangement of working the slides, and changing the motion of the eccentrics; nothing more is required to reverse the direction of the engine, than to move the handle, н, from one position to the other.

Figs. 1 and 2, Plate XII. are a side view and elevation of a locomotive engine complete, the middle wheels, being those to which the steam is applied, and being larger than the others. The figures in this plate have the same reference as in Plate XI. The handle, н, for changing the motion of the engine, is a little different from that described in Fig. 6, Plate XI., the mode of working the slides being different. p is the pipe leading from the water-tank to the force pump, for supplying the boiler with water. We have not shewn the plan of pump, but as the mode of working such pumps are so well known, except shewing the sort of clack generally used, we did not think it necessary to give any plates to illustrate the plan of working these pumps. We may, however, observe, that there are always two pumps attached to each engine, the constant and certain supply to engines of such rapid evaporating powers, being of the greatest consequence. The pumps are worked from eccentrics, on the axle of the wheels of the engine.

We have not given a plan of the tender, for carrying the coke, and water; these are made similar to other carriages in the frame-work and wheels, with a wroughtiron tank, of a quadrangular form, about two feet and a half high, and one foot and a half wide, around the sides of the platform of the carriage, open at the end next the engine, the space within being allotted for the deposit for the coke.

The plan of engine shewn in Fig. 1, Plate XII. is such as is used for the conveyance of passengers, or where the load to be taken is not great, or where a great amount of adhesion is not required; the driving wheels of this engine are five feet in diameter, calculated for a speed of twenty-four miles an hour. When heavy trains are to be propelled, or where the gradients of the

road is such that adequate adhesion is not obtained, four of the wheels are coupled together, by which a greater amount of adhesion is obtained; this is done by projecting the axles of the driving wheels beyond the frame-work of the engine, and cranking the ends; the axle of the other pair of wheels is made to project in like manner, and a horizontal rod between the ends of the crank, connects the motion of the wheels with each other; and, in some cases, as for the inclined planes on the Liverpool and Manchester line, and also for the Newcastle and Carlisle railway, all the six wheels of the engine are so coupled; the wheels, in this case, being of less diameter.

In the Great Western railway, which is made seven feet wide between the rails, and on which Mr. Brunel proposes travelling at a higher rate of speed, he has made his driving wheels of a larger diameter; and the Messrs. Hawthorn are now constructing an engine for that railroad, with driving wheels ten feet in diameter, calculated for a speed of forty miles an hour.

Tables of the Dimensions of Locomotive Engines.

We now give tables of the dimensions of several engines, constructed by Messrs. Stephenson and Co., and Messrs. R. and W. Hawthorn of Newcastle upon Tyne.