2011) Assessment of safety against derailment using simulations and vehicle acceptance tests: a worldwide comparison of state-of-the-art assessment methods,The assessment of derailment safety of new railway vehicle designs is a fundamental concern worldwide. Although the methods used for assessment in different countries and regions vary considerably, the fundamental mechanisms being addressed are the same. This paper provides a detailed review of the current state-of-the-art methods for derailment safety assessment in several regions and countries including Europe, UK, USA, and Russia. Brief overviews of the methods used in China, Korea, and Japan are also included. Similarities and differences are discussed, including testing and computer simulations. References are provided for the origins of the methods and safety performance criteria used in each region. Recommendations are made for improving the assessment methods, especially the use and validation of computer simulations.

No abstract

Wear of wheels and rails is a problem of substantial magnitude for railways throughout the world. Efforts to control wear by using new wheels profiled to match worn wheels have met with a measure of success. Purely empirical approaches to this problem require years of effort before results can be assessed. This paper describes a computational method for predicting worn profiles. The method is applied here to freight cars running on tangent track, and it includes the capability to handle both stable and hunting running. The method has been evaluated with four different wear models, and it was found that the predicted worn wheel profiles are relatively insensitive to the selection of wear model. Results include predictions from AAR and CNA wheels running on new rail, and from a simulated unit-train operation.

No abstract

An analytical and experimental study has been performed to determine the tension and bending stress concentration factors as a function of notch depth for 'U', 'V', and opposed 'U-'V' notches. Accurate results are produced using quadrilateral finite elements where the edge-lengths in the notch region are less than 10 percent of the notch radius, and using strain gauges where the active gauge length is less than 1/3 the notch radius. Results are presented for single 'U' and 'V' notches that are outside the range of previously published studies. A detailed stress analysis of a single notched specimen revealed the presence of a tension stress concentration factor ( K , > 1) and a bending stress reduction factor (K, -= 1) on the un-notched side of the bar directly opposite the notch. An approximate method of determining stress concentration factors for opposed 'U'-'V' notch geometries is presented.