Book Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1869 edition. Excerpt: ...on ballast, and 2,640 square feet of bearing of rails on timbers. The upper timber, when decayed, could be easily slipped out at the sides. The whole would afford much vertical stiffness, the bearing surface would be near the rail, and the structure would be elastic. There is another mode, in which T-iron ribs, 25 pounds per yard, take the place of the vertical planking. This makes equal to a 65-pound rail, with 3,150 cubic feet of timber per mile, with the bearings as above. Either variety of the sandwich system may be considerably simplified, if a superior quality of iron is insisted upon, by making the rail as nearly right angular under its head as it can be rolled, so as to prevent the necessity of dressing the timber to fit the shape, for instance. The groove for the flange may be very cheaply made by fitting a circular cutter in an ordinary wood planing machine and passing the timber through in the ordinary manner. It has been objected that this groove will fill with ice in winter, uponNorthern roads--because ice occasionally forms entirely across the road-bed between the rails, to a height which sometimes carries the wheels on their flanges and causes them to run off the line. Now, since the timbers would not necessarily touch each other within an inch or more, at their ends, any rain or snow water would run out of the groove. It is possible, however, that the groove might fill with sleet which would gradually turn to ice, and thus lift the flanges. This can be only settled by experiment. The timbers may be trimmed should this prove a serious objection. The last-named plan--raising the tread of the rail high enough to clear the flange--requires a little more weight of metal, but it most effectually prevents trouble from ice, and it...