Although a large number of truck models have been put into service on the 1520 mm gage railways over the past ten years, the problem of an insufficient shear stiffness of a freight car truck still remains topical. This problem is a consequence of attempts to keep a sufficient degree of unification of new truck models with the 18-100 truck because this greatly simplifies the introduction of new trucks and allows one to make the best use of the existing maintenance and repair infrastructure. However, this also results in that new designs inherit many drawbacks of the 18-100 truck. One of its critical drawbacks is a low connectedness in a horizontal plane, which reduces the critical speed and increases truck component wear. A solution to this problem may be an auxiliary stiffening frame. This paper presents a new design of an auxiliary stiffening frame for the 18-100 truck. The design increases the truck shear stiffness, thus improving freight car dynamic performance and service life. Mathematical simulation, oscillation theory, and elasticity theory methods were used to design an auxiliary stiffening frame installable between the 18-100 truck side frames without any significant changes in the freight car basic design. The physical and mechanical properties of the auxiliary stiffening frame’s structural materials were selected. Loads on the auxiliary stiffening frame were determined and then used in the calculation of the stresses that develop therein in motion. It was found that the proposed auxiliary stiffening frame with resilient polyurethane inserts increases the truck shear stiffness by 0.5 MN/m. The proposed improved design of the 18-100 truck increases its shear stiffness, improves freight car dynamic and operational performance, and reduces truck component wear. Besides, the auxiliary stiffening frame is simple in design. Because of this, its introduction will bring considerable economic benefits.

The development of new-generation trucks is highly topical for Ukrainian freight car fleet renewal. Important criteria for the assessment of existing or new truck designs are car ride quality and car component interaction improvement, wheel and rail wear reduction, and operational safety enhancement. The geometrical and elastic characteristics of new components must reduce truck resistance to curving and increase car stability both in tangents and in curves. The aim of this work was to develop recommendations on the choice of elastic parameters for additional links in trucks of prospective freight cars. Use was made of methods of mathematical simulation, numerical integration, oscillation theory, and statistical dynamics. This paper presents the results of investigations into the choice of parameters for new components to be used in 18-7020 trucks: diagonal cross-braces between the side frames and an elastic adapter in the axlebox assembly. Emphasis is on the study of the wheel climb stability margin at different speeds in tangents and in curves. Advisable elastic parameters of additional links between truck components are determined. It is concluded that the best effect is achieved when both elastic adapters in the axlebox assemblies and elastic diagonal cross-braces between the side frames are used in 18-7020 trucks, which allows one to increase freight car speed, stability, and ride quality.