Updating the Design Map of Frost Indexes as a Prerequisite for Relevant Assessment of Track Substructure for Non-Traffic Load

The initial part of the paper briefly characterizes the present state of the track substructure dimensioning for the non-traffic load and the necessity of updating the design map of frost indexes IFd as a basis for dimensioning. A substantial part of the paper is dedicated to the method of evaluating the data provided by the Slovak Hydrometeorological Institute (SHMI), and determining the dependency of design air frost indexes IFd on altitude for the coldest winter period in the past 50 years. The paper conclusion presents the updated design map of frost indexes and the assessment of the importance of its updating in terms of the track substructure dimensioning methodology for the non-traffic load.