RISK ANALYSIS BASED CWR TRACK BUCKLING SAFETY EVALUATIONS.
As part of the Federal Railroad Administration’s (FRA) track systems research program, the US DOT’ Volpe Center is conducting analytic and experimental investigations to evaluate track lateral strength and stability limits for improved safety and performance. This paper deals with a part of this research addressing the development of a comprehensive CWR buckling safety analysis which includes a risk analysis based approach for prediction of probable number of buckles on a given track. These risk based buckling evaluations are particularly useful for dealing with statistical variability in the track parameters. The risk approach can provide economic options for track maintenance to achieve the desirable buckling strength. The buckling risk methodology and the statistical parametric descriptors are discussed and a buckling risk analysis model is presented with illustrative examples. The model also provides a computational scheme for the determination of buckling probability as a function of maximum rail temperature when the key influencing parameters of track lateral resistance, lateral alignment defect and rail neutral temperature are given as statistical variables. The risk based approach as well as the previously developed deterministic approaches in CWR-BUCKLE and CWR-INDY are all being integrated in a single new computer program called CWR-SAFE. CWR-SAFE is a Windows based software analysis package for a comprehensive buckling safety evaluation for use by both the railroad industry and the research community.
DYNAMIC BUCKLING OF CONTINUOUS WELDED RAIL TRACK: THEORY, TESTS, AND SAFETY CONCEPTS
A versatile, dynamic buckling model that can be used on a personal computer is presented. The model accounts for vehicle load influences and nonlinearities in track resistance, hitherto ignored in the literature. These influences are shown to be important in the accurate predictions of buckling response and hence in buckling safety considerations. The model also computes the energy required to buckle the track and thus indicates the levels of safety at given rail temperatures. On the basis of the energy and the upper and lower buckling temperatures derived from the model, rational buckling safety criteria have been developed. Results of controlled full-scale dynamic buckling tests conducted on tangent 5-, and 7.5-degree continuous welded rail track are presented and correlated with theoretical predictions from the model on buckling temperatues, forces, and safety limits.
America Or Europe?: British Foreign Policy, 1739-63
International developments Britain and the War of the Austrian Succession Anglo-French relations the Crown Parliament diplomats and ministers defence, foreign policy and strategy Pitt and moves towards new strategies, 1755-63 conclusion - Europe or America?.