In some situations, the level line of trackage is pre served by the occasional introduciion of inclined planes. on which the wagons are transported by machinery from one level to another, impelled generally by *team, water, or animal force. Where the load is all in one direction, as at the collieries of Newcastle, the slate quarries of Penrhyn, and in many other places, the empty wagons are drawn up inclined planes by the descent of the full ones. This improvement is said to have been first introduced at the Tyrone collieries in Ireland, by 1\4r. Davis Duckhart, an engineer of the Sardinian service. Notwithstanding the extensive application of the inclined plane to railways, both with and without the use of the steam engine, it still remains a desideratum to obtain some effective mode of lockage or perpendicular lift, which shall be more commodious to the circumstances of an undulating tract of country. Surely, in the present advanced state cf things, it cannot prove any serious obstacle to the efforts of professional men, to provide a convenient apparatus, capable of lifting a train of railway waggons seriatim on the principle of canal lockage. In suggesting such a machine, it will per haps be better to avoid views which may be consi dered speculative, and apply such as are more or less known in practice. We shall therefore first notice one which we have seen very prettily exemplified upon the small scale in the Lanark cotton-mills, where it is worked by a power taken from one of the water-wheels of these works. The contrivance is employed for con veying the cotton to the hands of the spinners in the upper stories of these extensive mills. A similar ap paratus is employed, upon the large scale, by Air. Baird, at the Shotts iron-works, where the machinery is impelled by a steam engine, of the power of six horses, for raising the minerals from the under ground workings. But any power adequate to the purpose may be applied to the lying shaft of this ap paratus, which altogether is simple in its structure, and very complete in its operation. In so far as it is ap plicable to our purpose, we shall term it a Railway-lock. It consists of two large cast iron wheels placed upon the same axis, at a convenient distance from each other, to admit of a railway wagon being suspended between them. Upon the peripheries of these wheels, teeth of a certain description are formed calculated to hook into the continuous links of what is technically termed a Pitch-chain. When wagons are to be raised or lowered from one railway to another, the machine is set in motion, and the pitch-chains upon which the wa gons are hooked ; or by different arrangement of the ap paratus they may be placed upon a platform connected with the pitch-chains, and thus moved from one level to another, by the revolution of the machinery, as will be more fully understood from Plate CCCCLXXVII, and its technical description.
Another machine, suitable for lifts upon a smaller scale, which may also be worked by any convenient power, is described in Stevenson's Account of the Bell Rock Lighthouse, at page 508, undo: the appellation of a Sherr-crane, the machine being represented in Figs. 1. and 2. Plate XI. of that work. The sheer-crane was worked by manual labour at the Bell-Rock, where it was employed for raising blocks of stone out of boats and laying them upon railway wagons; the lift vary ing from three to seven feet, according to the state of the tide.
In laying out a public railway, a breadth of not less than twenty feet should always be contemplated, so as to admit of two entire sets of tracks, with the necessary sides, paths, and drains. In a private road with one set of tracks, a space of twelve legit in breadth may be found sufilcient ; but in this case it is generally neces sary to make provision for about four passing places in each mile. But this description of mad should sel
dom he resorted to for a public railway, against which the inconveniency of the heavy drag at the turns of the passing places, and the frequent stoppage of the wa gons, should prove sufficient objections, especially as the economy in forming and making such a road will not be found great after every thing has been ta ken into account. It is further of importance to the steady motion of the wagons, particularly in high winds, that they he made rather of a broad and low construction, and that the railway tracks should not be laid at less than four feet a:iart, which will afford a sufficient tracking-path for the horse, without his being apt to injure the props of the rails. Attention should also be paid to the thorough drainage of the road, that the horse path rests upon a firm bottom, be finished with a smooth and compact surface, and made altogether of the best materials the country through which it passes can afford.
In the construction of railway-tracks timber and cast iron have hitherto been chiefly employed, but malleable iron is now coming into very general use. The great expense of malleable iron, and perhaps the want of im portance formerly attached to railways as a mode of ge neral traffic, were the chief hays to its introduction into the railway system ; but, strength for strength, we be lieve it can always be furnished as cheap as cast-iron. It has sometimes been objected to malleable iron, that it is liable to oxidation or rust, and that it may yield, with out its being observable, while the work may thus be continued, under a disadvantageous power, and that it were even better that a rail should break than be thus liable to distortion. These objections, however, appear to be rather of a negative description. With regard to the process of oxidation, it does not seem to carry much weight ; as railways of malleable iron may be seen at Lord Carlisle's works at Tynedale-fell, which have been in use for ten years, without appearing to have suffered materially in this respect. The advantages of malleable iron rails are manifest in their not being lia ble to break, and in diminishing the number of joints. To prevent their yielding in a hurtful manner, it is only necessary somewhat to increase the number of props, and instead of a junction at the distance of every three or four feet, the bars may be extended to twelve or eighteen feet, or might, indeed, by welding, be formed of any length. Upon the whole, therefore, we are inclined to give a decided preference to the use of malleable iron for railway tracks. In the year 1820, the Bedlington iron company of Northumberland were induced to take a patent for certain improvements in the construction of malleable iron rails, suggested to that company, from the perusal of Mr. Stevenson's Report on the Edin burgh Railway in 1819, as noticed in the printed remarks attached to their specification. The patentees insist chiefly upon forming the bars of a prismatic figure, and some other particulars, intended to improve their stability. The manner in which these rails are drawn and manufactured is highly creditable to the works at Bedlington ; but in recommending malle able iron for railway tracks, we have always had in view the simplest form of the bar with parallel edges. Whether malleable or cast-iron be adopted, the rails should be of the edge form, and be more massive and strong than they commonly are; of the former material for loads of about three tons on a public railway, they should not be less than So lb. and the latter 45 lb. per lineal yard, of single rail, and so in proportion, as the weight to be carried is more or less. It is pro per, however, to observe, that a little additional weight of metal, in the first instance, in making a substantial apparatus, will in the end prove great economy.