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British Industrial History

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Engineers and Mechanics Encyclopedia 1839: Railways: John Hawks

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The great success which attended the improvements of the railway bars by Messrs. Losh and Stephenson, already described, seems to have stimulated rival manufacturers in the same undertaking; for we find that in the following year (1817) a patent was granted to John Hawks, of Gateshead, Durham, for "a new method of making iron rails, to be used in the construction of railways."

The rails at that time in use, were, for the most part, cast iron; and those which were of malleable iron were merely square or flat rolled bars, and were, consequently, as liable to be bent, as the cast were to be broken, by the heavy weights and concussions to which they were continually subjected.

To obviate those defects, Mr. Hawks proposed to combine the properties of the two different kinds of iron, so that the combination should possess the rigidity of the cast metal against dead pressure, and the tenacity of the wrought to tie the cast metal together, should it become broken by percussion. The specification states that-

"Instead of making the rails or bars of cast or malleable iron, as those now in use are, they are a compound of malleable and cast-iron, so connected as to be stronger than if made of either kind alone. The surface is formed of cast iron, and the back, or under part, of malleable iron, joined together and formed when the metal of the former is in a fluid state; and they become so inseparable that the cast iron may be broken at the nearest possible distances; indeed, even inch by inch, which is scarcely possible to be occasioned by accident, and the rail will remain sufficient for the purposes of a railway at least, till it suits the convenience of the workmen to replace it, without interruption to the concern in which the railway may be used: and as a loss by a broken rail of this invention will be less than one in common use, the expense, although it may be a little more in the first instance, will be considerably less in the end, as the malleable iron may be used again, or as the old iron will be of much more intrinsic value than the other."

The modes of combining cast and malleable iron together in the rails are various; but that which Mr. Hawks prefers, as affording the best security for their being firmly fixed together, is by running the cast iron, when in a state of fusion, on the malleable iron; to effect which the malleable part is to be first forged, or otherwise prepared in that form and of that strength which the nature of its intended purpose or appropriation points out as most proper. That part of the malleable iron which is intended to be combined with the cast iron should be rendered rough and uneven by jagging or by perforation; by giving it a dovetailed form, or by any other means, so that the cast iron may firmly adhere thereto, without the liability of becoming loose by the violent action of the carriages.

The malleable part must be clean, perfectly, dry and warm, when laid in the mould to receive the melted iron, which should be poured in as soon as possible after the mould is ready to receive it, as any damp on the malleable iron will endanger the soundness of the cast iron part.

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