Engineers and Mechanics Encyclopedia 1839: Railways: John Birkinshaw
Although the invention of John Hawks, was exceedingly ingenious, and the execution highly creditable to the mechanical skill of our "workers of iron," its success, as applicable to the construction of railways, was of short duration; for in October, 1820, the specification of John Birkinshaw of the Bedlington Ironworks, in the county of Durham, was enrolled for a mode of constructing rails entirely of malleable iron, the process of which is so simple, and the result so excellent, as scarcely to leave any sluing more perfect to be desired; all the bars of our present edge-railways are made by this process, and are but slightly modified in form.
Previous to Mr. Birkinshaw's improvements, the edge-rails were chiefly of cast iron, resembling, for the most part, those described under Messrs. Losh and Stephenson's patent; and those which were formed of malleable bars were of the sectional shape, designated in the annexed figures in the margin, the first being technically called flat, and the second square bars.
Mr. Birkinshaw's attention was first drawn to the subject of substituting malleable for cast iron rails, by reading a Report made by Mr. Stevenson at that time, on the Edinburgh Railway. At page 26 of that Report, the author remarks, -
"One point, however, deserves particular notice here, as likely to be attended with the most important advantage to the railway system, which is the application of malleable iron instead of cast iron rails. Three miles and a half of this description of railway have been in use for about eight years on Lord Carlisle's works, at Tindal Fell, in Cumberland, where there are also two miles of cast iron rail; but the malleable iron road is found to answer better in every respect. Experiments with malleable iron rails have also been made at Mr. Taylor's Works, at Ayr, and Sir John Hope's at Pinkie; and, upon the whole, this method, as in the case of the Tindal Fell Railway, is not only considerably cheaper in the first cost than the cast-iron railway, but is also much less liable to accident. In the use of malleable iron bars, the joints of the railway are conveniently obtained about twelve feet apart, and three pedestals are generally between each pair of joints."
Previous to, and at the period of Mr. Birkinshaw's patent, a considerable degree of prejudice existed against the use of malleable iron rails, on account of their supposed liability to waste by rust. To settle this question by the test of experience, the agent of the earl of Carlisle, at Tindal Fall (where extensive lines of both kinds of rails were in use, as already mentioned) was applied to for information on the subject.
In a letter dated May, 1819, to Mr. Birkinshaw, that gentleman said-
"Our rails are one and a half inches square, and stand upon stones about ten inches square, and are placed at one yard distance from centre hole to centre hole. Our railway carries four tons weight, and has never cost us any thing yet, as to expense of the malleable iron, except creasing. The iron I cannot see the least alteration with, although it has now been laid eight years. The cast iron is a daily expense; it is breaking every day."
The causes of the preservation of malleable iron bars, exposed to the weather, from rust, and their slow wear, may be readily supposed to be the constant friction to which they are subjected by the traffic, and to the condensation of the upper surface of the metal by the heavy weights rolled over it, which, produces a hard compact coat, like that produced by cold-hammering steel and copper plates.
The facilities which cast iron presents, of enabling the engineer readily to mould and run it into such forms as will combine the utmost strength with else least quantity of material (individually considered), made it, for a long time, a favourite; but the necessity of guarding against breakage, owing to the brittleness of the substance, occasioned them to be made so much heavier than the malleable, as to render the latter even of less first cost than the cast metal.
It was from considerations of this nature that Mr. Birkinshaw was induced to attempt those improvements that are described in his specification; an extract from which we shall now make, it being particularly worthy of notice, as it is descriptive of the first and perfectly successful attempt to roll iron bars of those varied and useful forms, which so much abridge the labours of the smith and engineer, and give a higher degree of excellence to the products of their workshops:—
"My invention consists in the adaptation of wrought or malleable iron bars or rails of a peculiar form, instead of cast-iron rails, as heretofore. From the brittle nature of cast iron, it has been found, by experience, necessary to make the bars of a railroad sufficiently strong to bear at least six times the weight intended to be carried along the road, by which the original cost of a railroad. was considerably augmented; or if light rails were used, the necessity of frequently repairing entailed a heavy expense upon the proprietors.
“To obviate these objections, I have invented a bar to be made of wrought, or malleable iron, the original cost of which will be less than the ordinary cast iron rails or bars, and, at the same time, will be found to require little (if any) reparation in the course of many years. The rails or bars which I have invented are formed as prisms, though their sides need not of necessity be flat. Figs. 1 and 2 show sections of the bar thus formed; the upper surface upon which the wheel of the carriage is to run is slightly convex, in order to reduce the friction; and the under part rests in the supporting-blocks, chairs, rests, standards, or pedestals, which are mounted upon the sleepers. The wedge-form is proposed, because the strengths of the rail is always in proportion to the square of its breadth and depth. Hence this form possesses all the strength of a cube equal to its square, with only half the quantity of metal, and, consequently, half the cost. Sufficient strength, however, may be still retained, and the weight of metal further reduced, by forming the bars with concave sides, as shown in section, by Figs. 3 and 4. The mode of making iron bars of a great variety of forms, we have already generally explained in our account of the iron manufacture.
We shall therefore briefly describe here Mr. Birkinshaw's rollers, with reference to the following figure, which represents an elevation, or side view, of a pair of them. It will be observed, that the peripheries of each roller are indented with a series of grooves, like mouldings; each groove, except one in this upper roller, corresponding in form with another in the lower roller that is opposite to it; and that the figures represented by the hollow spaces left between the pair of rollers, are produced by the opposite surfaces being brought into contact.
It will therefore be obvious, that when a red-hot bar of iron is applied to the grooves of such rollers, forced round by a powerful steam-engine with great velocity, the iron will be compressed into the same form throughout its length. The form of rail now most approved of, which we shall have occasion hereafter to describe, is made by the same kind of machinery just noticed.
It may be deserving of remark, in this place, that Mr. Birkinshaw suggested at the end of his specification, that his railway bars (eighteen feet long) should be welded together, end to end, continuously, so as to form an extensive line without any joint, and thus avoid the jolting and concussions consequent upon the carriage wheels striking against the ends of each length of the ordinary rails, where they are connected to the chairs. The introduction of this suggestion serves to show what great mistakes are made, sometimes by the cleverest men, for want of a little reflection and we make no doubt that the patentee became soon sensible of what most of our readers are aware of; that a rail so constructed, without any provision for the expansion and contraction which takes place in the metal from atmospheric changes of temperature, must inevitably soon be thrown into ruins by the twisting of the rail, and the continual motion of the chairs and sleepers. And our only motive for thus noticing so singular an oversight is that the inexperienced and confiding reader of the specification may not fall into a similar error.
The long wood-cut in the margin was designed by Mr. Birkinshaw, to exhibit his improved railway and the long train of loaded coal waggons drawn by a single horse, serves to show the kind of waggons, and the nature of the power in general use at the period of the patent, 1820.
Mr. Birkinshaw also proposed the form of rail shown in the annexed figure, which, he says "may be used to advantage in some situations," without, however, specifying them. We shall therefore take leave to remark in this place that it is particularly suited to the top surface of Mr. Palmer's suspension railway, an invention of great merit, which will presently appear in its chronological order.
The eminent success of Mr. Birkinshaw's new rails had the effect, as might be expected, of stimulating the proprietors of rival and. neighbouring iron works, to try their skill in the same field of invention.
Hence we find Mr. William Losh, of Newcastle-upon-Tyne, obtaining an exclusive privilege for his "certain improvements in the construction of iron rails for railroads," on the 14th of September, 1821; which we find explained, in the enrolled parchment, to consist, -
"First, in using, placing, and fixing bars of malleable iron on the upper surface of a line of cast-iron rails or malleable iron rails, of whatever form such rails may be in the longitudinal direction of the rails when laid, so as to form an uninterrupted line the whole length of the bar, which may be as long as it shall be found convenient and economical to use, and of the same breadth as the upper surface of the rails to which it is fixed, or a little broader or narrower.
“Secondly, in some cases I fix a band or strap of malleable iron to the under surface of rails made of cast-iron, in order that such band or strap may, by its power of tension, give support to the cohesion of the parts of the cast-iron rails and admit of its being made lighter, and thus save expense, while it adds to security front breakage.
“Thirdly, I claim as an improvement, a rail formed by fixing two bars of malleable iron on their sides or edges, and fixing them in that position by bolts and studs, or by any other convenient method; and on their upper edges placing and fixing a flat bar of malleable iron, or one which is slightly curved or rounded at the edges, to diminish friction, so that the bar or plate, placed and fixed on the upper edges of the two malleable iron bars, shall form the surface upon which the wheels of the waggon or carriage are to revolve."
The inventor next proceeds to give "a full and particular description of all and every" of his modes and contrivances for connecting the parts of this compound rail; but as these are of too uninteresting a nature to please the general reader, and quite unnecessary to the practical man, We shall omit them. It is not, however, to be wondered at, that Mr, Losh, who was a great iron-founder, should endeavour to protect his own metal by a species of conservative reform, against the sweeping radical changes advocated by Mr. Birkinshaw; but all the "bolts, chains, rivets, and straps" of the former have entirely failed in supporting the conservative fabric, and the iron rule of Birkinshaw which first manifested itself amongst the collieries of the north, has since been powerfully demonstrated at Liverpool and Manchester, is now about to extend itself to Birmingham and London, and will, doubtless, soon embrace every town in the empire.