This study examines the modernization of the 61-4179 TVZ passenger coach for transporting light automobiles up to 3 tons, addressing the efficiency of multifunctional rail use. The objective was to assess how additional mass–dimensional loading influences strength, load distribution, and the dynamic stability of the vehicle–track system. Finite element simulations in ANSYS Workbench 2021 R2 determined stress distribution, deformations, and safety margins, while multibody dynamics modeling in Universal Mechanism evaluated wheel–rail contact forces, carbody accelerations, and stability coefficients. Field tests on curves with radii of 350 m and 300 m at 60 km/h validated the models. Carbody accelerations were 0.65–0.68 m/s², below the 0.7 m/s² regulatory limit; wheelset attack angles remained under 0.01 rad; and derailment safety coefficients were 1.6–1.8, all meeting international standards. Uniform load distribution maintained stability and suppressed oscillations. However, critical scenarios (wheel wear, extreme flange clearance, higher speeds) produced parameters approaching threshold values. To mitigate risks, clearance adjustment per δ₀ standards, a 1:20 guard-rail inclination, and optimized crossing profiles are proposed. These measures reduced lateral dynamic forces by 12–15% and raised the strength coefficient by 1.2–1.3. The results confirm technical feasibility, operational safety, and extended service life, supporting sustainable multimodal transport development.

This article presents an effective approach to mitigating vertical displacements of railway embankments constructed on weak soils, caused by precipitation, increased train loads, axial forces, and varying embankment heights ranging from 1 to 12 m. The stress–strain state of embankments founded on weak soils was analysed using numerical modelling based on the finite element method, supported by experimental and empirical data. The study examines the influence of static and vibrodynamic loads on the deformation behaviour of clay soils and railway embankments through laboratory investigations and numerical simulations, without considering filtration consolidation and time-dependent effects. Various strengthening measures were analysed, including stabilising berms, partial replacement of weak soils, and cement-based reinforcement techniques. Finite element models were developed to evaluate the stress–strain behaviour of embankments under different reinforcement scenarios. The results demonstrate that the application of integrated strengthening measures can reduce vertical settlements by 35–40%, decrease horizontal displacements by up to 25%, and significantly extend the service life of railway embankments without the need for major repairs. Based on the obtained results, recommendations are proposed for selecting optimal materials, reinforcement technologies, and injection methods suitable for different types of weak soils. The findings contribute to improving the reliability and operational safety of railway infrastructure constructed on weak ground conditions.

This article presents a comparative analysis of the distribution of intermediate rail fastening systems installed on reinforced-concrete sleepers across the JSC «NC Kazakhstan Temir Zholy» (JSC «NC KTZ») network, based on operational statistics for 2017 and 2025. Four principal fastening system groups were examined: the KB-65 fastening system, clip-based SKL, GK1 systems, ZhBR-65/ZhBR-65Sh fastening systems, and the KPP-5 anchor-type fastening system. The methodology included a comparative assessment of track lengths by fastening type, a synthesis of technical and regulatory characteristics, and an analytical calculation of longitudinal resistance to rail creep and the rail "breathing" zone for CWR track with KB-65 and SKL, GK1 systems. Between 2017 and 2025, the share of SKL, GK1 systems increased from 22.9% to 53.3% (+5,907.84 km), whereas the share of KB-65 systems decreased from 52.3% to 30.6% (−909.43 km). The calculation showed that the transition from KB-65 to SKL, GK1 systems increases longitudinal resistance to rail creep by 25%, from 14.72 to 18.40 kN/m, while reducing the rail "breathing" zone length by 20%, from 83.5 to 66.8 m. The findings confirm the transition towards resilient baseplate-free fastening systems and substantiate the need for standardised diagnostics of the sleeper-fastening assembly. The obtained results may be applied in selecting fastening systems for major track repair sections and in substantiating measures to enhance the stability of CWR track on the JSC «NC KTZ» network.