5.1 Introduction Gauge 0 Guild（5.1介绍计0公会）.pdfVIP

Part 2 Section 5 CAUSES OF DERAILMENTS Issue Date August 1998 5.1 Introduction Derailments are caused mostly by defects in either the vehicle or the track. As in the prototype they Gauge reduced can occur from a combination of track and vehicle defects or characteristics which in isolation would not necessarily cause a derailment. Part 1, Section 1 of the Guild Manual contains a full explanation of the critical dimensions of wheelsets and pointwork crossings, including drawings of gauges to check them. Figure 1 illus- Figure 2 trates the relationship of these dimensions. Pin fixed centrally causing sleeper distortion. Whilst the gauges prove that the dimensions of wheelsets and crossings are correct, they are not a complete check because they do not reveal axle b) Misaligned joints misalignment, (either temporary on sprung axles These are most likely to occur on heavy section rail or permanent on rigid ones), track twist or cross- where the fishplates may not hold the rails in true ing misalignment. These three defects are proba- vertical alignment. This defect is unlikely to cause bly the most common causes of persistent derail- derailment on straight track because the taper on ment. the wheeltreads keeps the flanges clear of the rail face but it is a common cause of derailment on sharp curves due