Scientific paper ID 1674 : 2018/3

Following one of the main objectives set - the creation of a calculation method for determination of the security against derailment, which corresponds to the approved by BDS EN 14363 and UIC code 518 experimental method with the same purpose - it is necessary, as a first step in this direction, to adapt the Nadal virtual model to the real (factual) facts while preserving some of its fundamental prerequisites, first of all - one point. In such ments calculation method is subject to a systematic improvement as authoritative assessment of its use in practice and its suitability may be given depending on the future development of the sufficient experimental results in quantity and quality. The adaptation in question is done through a dedicated model, which is closer to reality than Nadal`s model, respectively of BDS EN 14363 and UIC code 518, taking into account as a parameter the ratio of the vertical load of the non-attacking to the attacking wheel on the wheelset. In the created conditional system, when defining the boundary formula for the derailment criterion, an additional article is introduced, with distinction from the Nadal`s formula, with which new parameters are introduced. The limit value of the derailment criterion under the influence of the parameter takes into account the ratio of the vertical load of the attacking wheel to the non-attacking wheel from a single axle is reduced.