No abstract

In the present study, the problem of railway stiffness transitions, for example, railway tracks near bridge abutments or tunnels, was investigated numerically in terms of track deterioration and passenger comfort utilising two types of analysis. The first analysis employed a train–transition curve model which simulates the response of the train to deflection changes in the vicinity of the transition zone. The second analysis used a three-dimensional (3D) finite-element representation of the railway track interacting with a passing train. The effects of train speed, track stiffness changes and the presence of a track fault were addressed. The findings of this research are compared against available studies in the literature and recommendations are given towards an appropriate engineering design of transition zones.

No abstract

Recent research has highlighted the effect of the individual contributions of the crib, shoulder, and base resistance to the lateral behaviour of a typical railway sleeper under loading. The contribution of the shoulder ballast has been seen to provide around 30 per cent of the lateral resistance for an unloaded sleeper. The addition of extra ballast in the shoulder area provides a very limited increase in lateral sleeper resistance. It is common in areas of high lateral loading, such as switch and crossings, to provide sleeper end plates to improve the passive resistance of the track. Sleeper end plates have, however, many disadvantages, not least is the need to disturb the ballast in order to facilitate their installation. The application of polyurethane reinforcement of the ballast shoulder to rapidly form an in situ GeoComposite shoulder beam (geobeam) has many advantages over end plates, including the ability of the lateral beam to be installed directly after the track geometry has been corrected; the lateral track geometry can then be 'captured' at installation. The beam can also be formed while the trains are still running. In this article the application of lateral GeoComposite side beams to improve the passive resistance of the shoulders is illustrated through analytical and numerical analysis. The application of the technique to actual problem sites is also presented and the performance of the technique at the Harford bridge transition site discussed.