Improvement alternatives for railway track formation

The performance of the railway track system results from the complex interaction of its components in response to train loading. The railway track substructure has been given much less consideration, even though it has a major influence on the track deterioration and as a consequence on the costs of track maintenance and renewal. The properties of the substructure components are much more variable and difficult to determine than those of the superstructure. The importance of the track formation properties for track performance is discussed in the first part of the paper. In cases where the formation is too weak, the resulting high cost of track maintenance may dictate the need to improve the formation conditions. The paper contains the alternatives of track formation improvements separated in six groups: altering formation properties in place, reconstruction and replacement, asphalt-concrete application, slip stabilization, insertion of protective layer and geosintetics implementation. In the summary the evaluation process of proper formation improvement method is explained. The goal of the paper is to provide the basis for track formation improvement design, which may result in railway tracks with optimum maintenance effort and traffic operability.