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TIES AND BALLAST |
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TIES AND BALLASTCrossties, the transverse members that support the rails and hold them in alignment, were originally untreated timbers. Although concrete ties have become more common, the majority of new ties are wood treated with creosote or some other preservative injected under pressure. The use of preservatives has increased the life of ties from 5 or 6 years to 25 or 30 years or more. Advances in track engineering have included increases in the size of ties and in the number used in a given length of track, and the establishment of rigid standards of quality. 
Crossties rest in a bed of gravel ballast and support the railroad tracks placed on top. Crossties are made of wood or concrete. The steel tracks are connected to the crossties by metal plates and fasteners. Ties are bedded in a layer of ballast, formerly consisting of various materials such as earth or cinders, but today in all main-line tracks consisting of crushed stone or slag in chips of specified size. The angular irregular shape of the fragments ensures a porous mass for good drainage, but at the same time permits interlocking, so that weight is distributed evenly over the roadbed. The depth of ballast under the ties ranges from less than 61 cm (24 in) to 76 cm (30 in). TIES AND BALLAST |
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TIES AND BALLAST |
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GOVERNMENT REGULATION OF RAILROADS: • INTRODUCTION • STATE REGULATION • FEDERAL REGULATION • EARLY 20TH-CENTURY REGULATION • THE DEPRESSION YEARS • POSTWAR ENACTMENTS • DEREGULATION MOVEMENTS |
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