Engineers and Mechanics Encyclopedia 1839: Railways: Harry Scrivenor

The great improvement in the construction of iron rails introduced by Mr. Birkinshaw in 1819, and described by us at page 93, have stood the test of experience, and are used now at nearly the same state as he left them. Malleable iron was thus substituted for cast, and at a cheaper rate. Heretofore the chairs into which the rails are fitted have been made of cast iron, probably on the supposition that there was no other mode of bestowing upon them their varied form, and massive parts, at a moderate cost; and the consequences of this notion may be witnessed in the thousands of broken chains which may be found along any of the considerable lines of railroad now being laid down. It is therefore with much satisfaction that we peruse the specification of the patent granted to Harry Scrivenor, of New Broad-street, dated November 6, 1832; the object of which is to construct the chairs and pedestals of railways of wrought iron, aid chiefly by means of the rolling process.

In the preceding Fig. 1, a-b represent a pair of cast-iron rolls designed for this object, and put in motion by the usual mechanism employed in iron-works. It will be observed that the series of grooves or indentations in their peripheries correspond with the several shapes which the metal is intended to take in its progress through these rollers, until it at length attains the exact shape required to form the chairs or pedestals. Thus, for example, the grooves at c-d must be adapted to receive an ordinary short thick bar of wrought iron, about two feet long, and six inches square, properly heated for rolling. The bar is first passed through the rollers at c-d, which causes it to assume the shape shown at j. It is then passed in succession through the other grooves on the rollers at k-k, l-l, m-m, n-n, whereby it successively takes the form shown at e-f-g-h.

Having thus obtained a long bar of iron of the sectional form shown at n, it is next cut into lengths for chairs, which is effected by the mill shears shown at Fig. 2, which are worked by the engine. These shears are provided with steel jaws to receive the chair as shown at v-w, in order that in cutting off the chair it may not be forced out of shape. The opening between the cheeks of the chair for the reception of the rail are at present left parallel; the next process is therefore to give these parts a more suitable form for holding down the rail. This is effected by making the chair red hot, and placing inside the recess a mandrill of the required shape, with which it is again passed through another pair of rolls shown in the annexed Fig, 3; by these the recess is impressed with the required form to adapt it for receiving the intended keys.

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