Over the past decades the vehicle manufacturers have been striving to reduce vehicle weight to minimize energy consumption and emissions in line with the key priorities of the environmental objectives of the European Union. These goals can be met by using high strength steels although their application raises numerous challenges in welding. In general, the railway vehicle body is made of ribs-stiffened shell structure which bears the load together with chassis. By the change of mild steel to high strength steel in these structural elements, joined with resistance spot welding (RSW), significant weight reduction can be achieved. Thanks to the results of material development now it is possible to use thermomechanically rolled high strength steels with relatively low carbon equivalent which can be ideal for the RSW of railway vehicles. In this paper the results of tensile shear (STS) and cross-tension (CTS) tests of resistance spot-welded joints made of t=3 mm thick S700M thermomechanically rolled high strength steel are presented. The main research scope was to elaborate a complex resistance welding process including the determination of optimal welding parameters based on STS and CTS tests. The optimal technological parameters were nearly the same for the two loading circumstances, however, a bit shorter cycle was justified during the optimization for the cross-tension strength. The value of the tensile shear force exceeded the minimum value specified by the AWS recommendation D8.1M by more than 22% with an electrode indentation depth of less than 5%.