We live in the age, when the speed and quality are in the front partitions of transport. Time between a presentation of a concept and production of a prototype is still shorter. There is mainly the field of automatization of systems. Purely mechanic systems are used in many branches less and less. This is also the case with the issue of a metro door presented by the authors. Manual opening of a door is not currently used. This manner of door opening has been replaced by pneumatic and electric systems. In the process of door design for the solved metro wagon, a pre-sliding type of a door was designed. In case of a metro vehicle, where opening and closing of the door is relatively often, the door and door mechanisms are significantly loaded. By this reason, extraordinary reliability requirements of their functionality have to be taken into account. These forces represent the effect of the door system on a wagon basic structure. Because this problem is quite large, the authors do not present all details related with the design of the door system, however, in this article, they focus mainly on parametrization of a model, which will serve for calculation of loading forces, methodology of creation of equations for calculation of the loads due to the pressure differences, as well as normative requirements in terms of other loads. In order to speed up the process of further proposals, the authors present the methodology of the process of parametrization for determination of force effects in the important structural unit.