A practical description of Herrons' patent trellis railway structure: also, the patent wrought iron railway chairs, new and improved mode of joining ... scarfing timbers, and improved fastenings

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1841 edition. Excerpt: ...of 15 feet. The plan Fig. 5, shows a more economical mode; the scarfings being placed opposite each other, half the number of transom sills will answer, as they are indispensable only at the joints. In the present case the transom sills are placed at distances of 20 feet, the string-pieces being supposed of that length. These transom sills are 10 feet long, and may be about 6 by 8 inches section; they are laid on the flat side, and notched on to the diagonal or trellis sills, leaving 2 inches of the transoms above the trellis, as shown in the cross-section, Fig. 8. There are also two suitable notches cut in the top of the transoms, 2 inches deep, for the string-pieces, d d, to rest in, and thus relieve the wooden pins, p p, &c., of undue lateral strain, which they might otherwise be subjected to near the joints. I consider the angular scarfing, A B, essential to the stability of the present track, and, resting it in the notch of the transom, together with its peculiar structure, will effectually prevent any tendency to splitting there might be in the ends of the stringpieces. Professor Barlow states that in 1817 malleable iron for the purposes of railways was unknown. The ends of the string-pieces d d, &c., by resting in the indents of the transoms h h, are effectually secured from depression and lateral deviation. The next object is to secure the string-pieces, in an effectual manner, on the intersections of the trellis sills a ca and b c b; this might of course be done by iron bolts, similar to the first track, or by having the top series of oblique sills of sufficient thickness to notch the string-pieces into them; but I desired to avoid the use and expense of iron bolts, and at the same time to hold the string-pieces down in their place...