Description :

Ballasted track becomes more and more important in railway transportation systems worldwide. Under heavy repeated traffic loading, the ballast would be damaged fast. If the damaged ballast are not well treated and maintained, the ballast will lost its strength to support the track against the train load in both of lateral and longitudinal direction safely. In the most extreme case, it will cause fatal accidents of derailment. Owing to its importance in railway safety, many monitoring and evaluation methods have been well developed. Current, the monitoring of ballast condition still relies very much on visual inspection and core tests. Although extensive research has been carried out in the development of non-destructive methods for ballast condition evaluation, a commonly accepted and cost-effective method is still in demand. It must be pointed out that visual inspection can only identify ballast damage on the track surface while track geometry deficiencies and rail twists can be detected using a track gauge. But ballast damage under the sleeper loading area and the ballast shoulder, which are the main factors affecting track stability and ride quality, are extremely difficult if not impossible to be detected by visual inspection. Core test is a destructive test, which is expensive, time consuming and may be disruptive to traffic. A fast real-time ballast damage detection method that can be implemented by permanent way inspectors with simple equipment can certainly provide valuable information for engineers in assessing the safety and riding quality of ballasted track systems. The main objective of this paper is to study the feasibility of using an instrumented hammer to excite an equivalent single degree-of-freedom system (SDOF), incorporating a concrete sleeper, rail and pad, to determine the dynamic properties of the damaged ballast using model analysis so as to explore the possibility of developing a handy method for the detection of ballast damage based on the measured vibration of sleepers.　

Biography:

Mr Wong Man Tat is working in the Permanent Way Engineering Division of the MTRC. He has over 25 years working experience in permanent way maintenance and design as well as railway incident investigation. He worked in some railway development projects including the construction of Tsing Ma Bridge railway and Lantau Airport Railway Olympic Station noise enclosure. He is a member of the China Hong Kong Permanent Way Society and is now pursuing the Engineering Doctorate (Building and Construction) Programme in the City University of Hong Kong.