Annual of Scientific Discovery

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: IMPROVED TRACTION UPON STEEL RAILS AND STEEL-HEADED RAILS. It has been too much the practice of railway managers to consider only the increased durability of steel. A less striking, but perhaps equally important advantage, is that it has double the strength and more than double the stiffness of iron. Some 3 years since, Mr. George Berkley made, in England, above 600 tests of the stiffness of steel and irpn rails of equal section. The rails were supported on 5-leet bearings, and loaded with dead pressure at the middle. The first rails tried weighed 68 pounds per yard, and loads respectively of 20 tons and 30 tons were applied. The average of 427 tests of the Ebbw Vale Co.'s and two other standard makers of iron rails, gave, with 20 tons, a deflection of flve-eightha iueh and a permanent set of one-half inch. With 30 tons the deflection was two and one-fifth inch and the permanent set two and one-sixteenth inch. With Brown's steel rails, 45 tests gave an average deflection of but five-sixteenths inch and permanent set of one-eighth inch. With heavier rails and loads, the comparative stiffness of steel was still more marked. The great and constant resistance of traction, and the wear and tear of track wheels and running gear, due to the deflection of rails between the sleepers and the perpetual series of resulting concussions, may be much reduced, or practically avoided, by the use of rails of twice the ordinary stiffness; in such a case, however, reasonably good ballasting and sleepers would be essential. When a whole series of sleepers sinks bodily into the mud, the consideration of deflection between the sleepers is a premature refinement. If the weight of steel rails is decreased in proportion to their strength, these advantages of cheaper traction and maintenance will not, ..