Railway wagons and intermodal units transported on train ferries are currently assessed with a dynamic model that considers only pure rolling of the vessel at cruise speed with rigid vehicle-deck coupling and deterministic wave parameters. The open problem, stated explicitly in the source study (Lovska et al., Sensors 2024), is to extend this load and strength assessment to realistic service conditions: several degrees of freedom of the railway ferry (such as heave, pitch, and their coupling with roll), stochastic sea-wave sequences and their effect on the fatigue strength and long-term durability of the wagon body secured by the proposed deck-fastening unit, cargo shift and asymmetric placement of a container on a roll trailer during rolling, and corrosive wear of the vertical sheets reducing the rigidity of the pivot beam under operational loads. The subsequent literature to date retains the single-degree-of-freedom deterministic rolling framework, so the core of the problem remains open.

Background

A train (railway) ferry is a roll-on/roll-off (ro-ro) vessel with rails laid on its decks so that loaded freight wagons can be rolled on and off, connecting rail networks across seas (e.g., the Black Sea routes between Ukraine, Bulgaria, Georgia, and Turkey). The wagons are secured to the deck by chain binders (tensioned lashing chains) and fastening units, and containers may ride on roll trailers (low wheeled platforms) or on flat wagons within combined transport trains. Because wagon bodies are designed for loads occurring in line operation on land, sea transport exposes them to accelerations and restraint forces outside their design assumptions; inadequately secured wagons have caused actual ferry disasters (the Mercury-2 train ferry, sailing between Azerbaijan and Dagestan, sank in the Caspian Sea in October 2002 during a storm with improperly secured rail cars). The relevant ship motions are the rigid-body oscillations of the hull: rolling (rotation about the longitudinal axis), pitching (rotation about the transverse axis), and heave (vertical translation); a single-degree-of-freedom model treats one of these in isolation, while real sea states excite them simultaneously and in coupled fashion. A series of studies by the University of Žilina and Kharkiv research group (Lovska, Fomin, Píštěk and Kučera in the Journal of Marine Science and Engineering 2020 and Applied Sciences 2020; Gerlici, Vatulia, Lovska and colleagues in TransNav 2024) built mathematical models of wagon loading during ferry rolling and used the computed accelerations as inputs to finite-element (FE) strength analyses of wagon bodies. Lovska, Gerlici, Dižo and Ishchuk (Sensors 24(1):183, 2024) extended that line: it derived a mathematical model of train-ferry rolling oscillations under the hydro-meteorological conditions of the Black Sea, computed a lateral acceleration of 3.1 m/s² at the wagon location (37% above the admissible line-operation value), confirmed body stresses by strain-gauge experiments, proposed a new fastening unit for securing open wagons to the deck (maximum equivalent (von Mises) stress of 304 MPa, about 30% below the typical fastening scheme), and determined the overturning stability of a container on a roll trailer up to 20° of roll. However, the model assumes the ferry moves in pure rolling at cruise speed, the wagon is rigidly coupled to the deck, the sea wave is treated deterministically, the container is fixed and uniformly loaded, and the fastening assembly is free of degradation. Fatigue strength — the ability of a structure to withstand many cycles of repeated loading — is decisive for long-term durability because random wave sequences impose highly irregular cyclic loads, and corrosive wear of the vertical sheets can reduce the rigidity of the pivot beam when accepting operational loads (the fastening units are mounted on the bolsters, the transverse load-bearing beams of the wagon underframe).

Problem Statement

Determine the dynamic load and the resulting strength, fatigue life, and stability of rail vehicles and intermodal units secured on a train-ferry deck under realistic seaway and service-degradation conditions, extending beyond the pure-rolling, cruise-speed, rigid-coupling, deterministic model of Lovska et al. (Sensors 2024). Specifically: (1) build a mathematical model of the vehicle-on-ferry system in which the ferry's motion includes several degrees of freedom (such as heave, pitch, and their coupling with roll) and derive the corresponding accelerations and loads on the wagon body and its deck fastening; (2) include the stochastic nature of sea waves and quantify the influence of random wave sequences on the fatigue strength and long-term durability of the wagon body, with the proposed fastening unit taken into account; (3) quantify the stability of a container on a roll trailer when the goods inside the container can shift during rolling and the container can be positioned asymmetrically on the trailer; and (4) quantify the effect of corrosive wear of the vertical sheets on the rigidity of the pivot beam under operational loads. The four parts address distinct aspects of the same dynamic-load, strength and stability problem, and resolving one part does not by itself resolve the others.

References

  1. Lovska, A., Gerlici, J., Dižo, J., Ishchuk, V. (2024). The Strength of Rail Vehicles Transported by a Ferry Considering the Influence of Sea Waves on Its Hull. Sensors, 24(1), 183. https://doi.org/10.3390/s24010183
  2. Gerlici, J., Vatulia, G., Lovska, A., Kravchenko, K., Harušinec, J., Suchánek, A. (2024). Determination Of The Loading On The Open Wagon Body When Rolling On The Train Ferry. TransNav, 18(3), 683–687. https://doi.org/10.12716/1001.18.03.23
  3. Vatulia, G., Gerlici, J., Lovska, A., Krasnokutskyi, Y., Harušinec, J., Šťastniak, P. (2024). Investigation Into the Dynamic Load of the Container with Sandwich Panel Walls when Transported by Train Ferry. TransNav, 18(1), 205–209. https://doi.org/10.12716/1001.18.01.21
  4. Lovska, A., Gerlici, J., Dižo, J., Blatnický, M. (2025). The influence of chain tie placement on the strength of wagon body components during transportation by a railway ferry. Acta Technica Jaurinensis, 18(3), 156–163. https://doi.org/10.14513/actatechjaur.00775
  5. Lovska, A., Gerlici, J., Dižo, J., Ravlyuk, V., Rybin, A. (2025). Strength analysis of sectional flat wagon supporting structures when transported by a railway ferry. Acta Technica Jaurinensis, 18(1), 46–53. https://doi.org/10.14513/actatechjaur.00771
  6. Gerlici, J., Lovska, A. (2025). Research of Loading of a Hopper Container During Sea Transportation by a Train Ferry. TransNav, 19(4), 1321–1326. https://doi.org/10.12716/1001.19.04.31
  7. Dižo, J., Gerlici, J., Lovska, A., Blatnický, M., Bučko, M. (2025). Features of Determining the Expansion Forces of Bulk Cargo Acting on the Wagon Body Walls When Transported by a Railway Ferry. TransNav, 19(4), 1327–1331. https://doi.org/10.12716/1001.19.04.32
  8. Lovska, A., Dižo, J., Blatnický, M. (2025). Study of loading of a universal container during sea transport. Cognitive Sustainability, 4(3). https://doi.org/10.55343/cogsust.20527
  9. Lovska, A., Okorokov, A., Muradian, A., Romakh, V., Bolvanovska, T. (2025). Determining the load on the bearing structure of a flat wagon for long cargo in rail-ferry transportation. Eastern-European Journal of Enterprise Technologies, 4(7(136)), 15–22. https://doi.org/10.15587/1729-4061.2024.335175
  10. Lovska, A., Gerlici, J., Dižo, J., Rukavishnykov, P. (2026). Identifying Features of Determining Strength of Container When Transported by Sea. Communications – Scientific Letters of the University of Žilina, 28(3), B110–B118. https://doi.org/10.26552/com.C.2026.034
  11. Lovska, A., Fomin, O., Píštěk, V., Kučera, P. (2020). Dynamic Load and Strength Determination of Carrying Structure of Wagons Transported by Ferries. Journal of Marine Science and Engineering, 8(11), 902. https://doi.org/10.3390/jmse8110902
  12. Lovska, A., Fomin, O., Píštěk, V., Kučera, P. (2020). Dynamic Load Modelling within Combined Transport Trains during Transportation on a Railway Ferry. Applied Sciences, 10(16), 5710. https://doi.org/10.3390/app10165710