Problems with Railway Track Drainage in Finland

Abstract

Several studies have shown that water plays a significant role in phenomena that weaken track geometry. For instance, water may cause frost heave, thaw softening, attrition of ballast, and weakening of the load bearing capacity of a track. Functioning drainage can prevent water damage, but no researched data on the magnitude of the impacts exist. Most of the Finnish rail network has been built in times when earthworks were kept to a minimum. Drainage generally functions well along new and renovated rail sections, but the situation is quite different with old tracks. If unevenness problems can be dealt with adequately by improving drainage, it is considerably more advantageous compared to massive renovation. The aim is to find out whether systematic improvement of drainage can produce significant savings in rail network maintenance. The study examines the unevenness problems discovered along the Finnish rail network where the functioning of drainage is thought to be a major factor, while seeking solutions to the problems. This article presents the technical and administrative problems related to drainage in the Finnish rail network. Based on observations made so far, even basic drainage solutions are beset with problems since e.g. ditches are not cleaned with sufficient regularity. The on-going study aimed to determine the impact of drainage on track unevenness at monitored sites. However, the method did not work as expected since no suitable sites, where other significant measures had not been carried out in connection with drainage renovation, could be found along the rail network. Moreover, it was difficult to get information about earlier renovation measures. It can be said already at this phase of the study that drainage maintenance should be improved. There are also problems with drainage assessment methods which consist mainly of visual inspection instead of more sophisticated methods. Subjective assessment methods and maintenance contracts that call for maintenance ‘as required’ easily lead to postponement of maintenance measures.