Engineers and Mechanics Encyclopedia 1839: Railways: H. R. Palmer
We must now, however, leave this part of the subject, to introduce to the reader an entirely different description of railway conveyance invented by H. R. Palmer, at present the engineer to the London Dock Company, and which was patented by him on the 22d of November, 1821.
Instead of two lines of rail laid upon the ground, as heretofore, Mr. Palmer's railway consists of only one, which is elevated upon pillars, and carried in a straight line across the country, however undulating and rugged, over hills, valleys, brooks, and rivers, the pillars being longer or shorter, to suit the height of the rail above the surface of the ground, so as to preserve the line of the rail always straight, whether the plane be horizontal or inclined.
The waggons, or receptacles for the goods, travel in pairs, one of a pair being suspended on one side of the rail, and the other on the opposite side, like panniers from the back of a horse. By this arrangement only two wheels are employed, instead of eight, to convey a pair of waggons; these two wheels are placed one before the other on the rail, and the axle-trees upon which they revolve are made of sufficient length and strength to form extended arms of support, to which are suspended the waggons or receptacles on each side of the rail, the centre of gravity being always below the palace of the rail.
The rods by which the waggons are suspended are inflexible; hence, although the weights on each side be not equal, they will, nevertheless, be in equilibrio; as may be observed in a ship, which, being unequally loaded, assumes such an angle with the surface as preserves the equilibrium. Although an equal distribution of the load on both sides is desirable, it is not necessary. A number of carriages are linked together, and towed along the rail by a horse, as barges on a canal. Owing to the undulation of the country, the horse will sometimes be much below the rail, its consequence of which he is provided with a sufficient length of rope to preserve a proper angle of draught.
Fig. 1 is an end view of the carriage, with a cross section of the rail, and a pillar, showing its form, and manner of fixing.
Fig. 2 is a side view of the railway passing over an uneven surface, with three of the supporting pillars of unequal length. Upon the upper surface of the rail are seen the two carriage wheels, and the manner of suspending the waggons or receptacles from the axletrees, which in however, better shown by Fig. 1, letters I-I-I-I.
Fig. 3 is a plan of the same, which exhibits the comparative measurements, and the mode by which the receptacles are braced together. The same letters of reference refer to the same parts in the different figures.
A in Fig. 1, represents an upright pillar of cast iron, having, at the shoulder, a flange, which rests upon the surface of the ground. The pillar is formed with ribs at right angles, which converge towards the lower extremity, and are notched in the edges, for the better securing it firmly in the ground. The hole in which it is to be inserted is to be previously well rammed, by a kind of pile-driving engine, and the foot of the pillar surrounded with hard materials, which are also to be rendered as compact as possible.
Three of these pillars are shown fixed in Fig. 2, placed about nine feet apart. At the upper extremities of the pillars are long clefts or openings, to receive the rail B, which is composed of deal planks, set on their edges, with their upper surface C defended by cast or wrought-iron plates, Is little convex on the upper side. When the rail has been some time in use, and all has taken a bearing, a little adjustment of the line may be requisite before the rail is bolted to the pillars; to effect which, a very simple and easy method is provided. In the cleft of the pillars, and under the rail, two wedges a-a are introduced in opposite directions, whereby its level may be adjusted with the nicest accuracy. The wheels D-D are provided with flanges, to keep them on the rail, and their peripheries are slightly concave, to adapt their surfaces to that of the rails. E-E are the arms or axles; H-H are the receptacles for the goods, which are made of plate iron, and are suspended to the arms, as before mentioned, by the inflexible rods I-I-I-I. To one of the arms a chain K is hooked, to which a towing-rope may be connected. Any number of carriages may then be attached together by chains hooked on to the angles.
The annexed Fig. 4 is intended to exhibit a portion of the railway in use, and the methods by which several of the obstacles which frequently present themselves are overcome. On the left is seen a jointed rail or gate that crosses the road over which the carriages have just passed, and the gate swung back, to leave the road open; the horse and man having just forded, the train of carriages is proceeding in its course, and following another train, part of which is seen on the right, crossing a rail bridge, simply constructed for that purpose.
Provision is made for trains of carriages that are proceeding in opposite directions, by means of "sidings" or passing places. With respect to loading, if both receptacles be not loaded at the same time, that which is loaded first must be supported until the second is full. Where there is a permanent loading-place, the carriage is brought over a step or block; but when it is loaded promiscuously., it is provided with a support connected to it, which is turned up when not in use.
From the small height of the carriage, the loading of those articles usually done by hand becomes less laborious. The unloading may be done in various ways, according to the substance to be discharged, the receptacles being made to open either at the bottom, the ends, or the sides. In some cases it may be desirable to suspend them by their ends, when, turning on their own centres, they are easily discharged sideways.
Among the advantages contemplated by the patentee of this railway, may be mentioned that of enabling the engineer, in most cases, to construct a railway on that plane which is most effectual, and where the shape of the country would occasion too great an expenditure on former plans - that of being maintained in a perfectly straight line, and in the facility with which it may always be adjusted; its being unencumbered with extraneous substances lying upon it; in receiving, no interruption from snow, as the little that may lodge on the rail is cleared off by merely fixing a brush before the first carriage in the train; in the facility with which the loads may be transferred from the railway on to the carriages, by merely unhooking the receptacles, without displacing the goods, or from other carriages to the railway, by the reverse operation; in the preservation of the articles conveyed from being fractured, owing to the more uniform gliding motion of the carriages; in occupying less land than any other railway; in requiring no levelling or road-making; in adapting itself to all situations, as it may be constructed on the side of any public road, on the waste and irregular margins, on the beach or shingles of the sea-shore, - indeed, where no other road can be made; in the original cost being much less, and the impediments and great expense occasioned by repairs in the ordinary mode, being by this method almost avoided.
A line of railway on this principle was erected, in 1825, at Cheshunt, in Hertfordshire, chiefly for conveying bricks from that town, across the marshes, for shipment in the river Lea. The posts which support the rails are about ten feet apart, and vary in their height from two to five feet, according to the undulations of the surface, and so as to preserve a continuous horizontal line to the rail. The posts were made of sound pieces of old oak, ship timber, and in a, the slot or cleft at the upper ends of the posts, are fixed deal planks twelve inches by three, set in edgeways, and covering with a thin bar of iron, about four inches wide, flat on its under side, and very slightly rounded on its upper side; the true plane of the rail being regulated or preserved by the action of counter- wedges between the bottom of the mortises, and that of the planks. By this rail, on the level, one horse seemed to be capable of drawing at the usual pace about fourteen tons, including the carriages.
The late Thomas Tredgold, whose opinion in matters of this stature will ever be entitled to attentive consideration, expressed himself very favourably to this invention in his 'Treatise on Railroads and Carriages': -
"We expect that this single railroad will be found far superior to any other for the conveyance of the mails and those light carriages of which speed is the principal object; because we are satisfied that a road for such carriages must be raised no as to be free from the interruptions and crossings of an ordinary rail way."
It has generally been considered a defect in Mr. Palmer's arrangement, that in order to make turns in the road, it is necessary that a portion of the rail should be made to turn with the carriages upon it.