Combined rail/water transport carries freight wagons by sea on railway ferries, where the wagons are secured to the deck tracks by chain binders, jacks, brake shoes and buffer stops and are exposed to ship-motion accelerations for which their carrying structures were not designed. The source study (Lovska, Fomin, Píštěk and Kučera, 2020) determined the dynamic load and strength of the carrying structure of an open wagon under a ferry roll model in which the wagon was rigidly fixed to the deck — an attached mass exactly repeating the ferry's motion — and explicitly declared the neglect of the wagon's own oscillations as the research limitation to be studied in further research. Follow-up work by the same research network has since incorporated wave-impact forces on the ferry hull, performed full-scale strain-gauge verification, proposed improved fastening units, and, for a flat-wagon–container–freight configuration, a four-degree-of-freedom angular model; however, no published strength assessment of a wagon carrying structure under ferry transportation couples the carrying structure's elastic oscillation modes to the ship's roll, and no experimental prototype of the proposed viscous binder has been reported. The problem — determine the dynamic load and strength of a wagon carrying structure under train-ferry transportation with the wagon's own oscillations (relative motion through its fastening and elastic oscillation modes of the body) coupled to the ship's roll, and reassess the typical and viscous-binder fixation schemes under this coupled model — remains open.

Background

Combined rail/water ('rail/ferry') transportation moves freight wagons by sea on specially equipped ships — railway ferries — for example on the Black Sea routes between Ukraine, Bulgaria, Georgia and Turkey, served by train ferries such as the Heroi Shipki. On board, each wagon stands on deck tracks and is secured by reusable lashing equipment: chain binders (eight per wagon), mechanical support jacks (four per wagon), brake shoes under the end wheels, and buffer stops. Because wagons are designed for rail loads only, the accelerations produced by ship motions at sea can damage their carrying structures, with damage concentrated in the fixation zones.

Lovska, Fomin, Píštěk and Kučera (2020) modelled this loading for an open (gondola-type) freight wagon. They wrote the equation of roll — the ship's rotation about its longitudinal axis, the ship motion most dangerous for the stability of deck cargo — excited by trochoidal wave kinematics (a classical trochoidal description of the orbital motion of water particles in a wave) and by wind pressure on the ship's above-water projection, and they treated the wagon as rigidly fixed on the deck, i.e., as an attached mass that completely repeats the ferry's trajectory, so that the wagon's own oscillations were neglected. The calculation was based on Black Sea operating conditions and the parameters of the Heroi Shipki train ferry fully loaded with 108 rail vehicles. The model was checked for adequacy with Fisher's F-test (a statistical comparison of the dispersion of adequacy and reproducibility) and gave a maximum acceleration of about 0.25 g on the wagon body. A finite element method (FEM) strength calculation of the carrying structure in SolidWorks/CosmosWorks under this load gave maximum equivalent (von Mises) stresses of 443.2 MPa in the fixation zones, exceeding the admissible value (yield strength 345 MPa). In that FEM model the hatch covers were omitted because they are not rigidly connected to the frame, and longitudinal forces through the automatic coupler were omitted because they are limited by buffer stops and brake shoes. The authors therefore proposed an improved fixation diagram with a viscous binder — a hydraulic chain-binder-like device (case, piston, throttle holes) that develops viscous resistance only when the load force exceeds 5 tonnes — and, modelling the wagon body's angular displacement relative to the deck through a linear viscous resistance coefficient β\beta, found accelerations reduced by about 30%, maximum equivalent stresses of about 280 MPa (within admissible values), and a 10% improvement in the wagon's stability against capsizing on the deck.

The paper's stated research limitation is precisely that the wagon's own oscillations were neglected, and the authors declared this the subject of their further research; the model additionally excluded the impact effect of waves striking the ferry hull, and the viscous-binder design was substantiated only by mathematical modelling. Later work by the same research network resolved the wave-impact exclusion — wave impact pressure on the hull was added, together with full-scale strain-gauge measurements on a ferry in the Black Sea — and modelled relative angular oscillations for a flat-wagon–container–freight system; but no published strength assessment of a wagon carrying structure under ferry transportation couples the carrying structure's elastic oscillation modes to the ship's roll. The unresolved target is a determination of the dynamic load and strength of the wagon carrying structure in which the wagon's own oscillations are genuinely coupled to the ship's motion.

Problem Statement

Determine the dynamic load on, and the strength of, the carrying structure of a freight wagon transported on the deck of a train ferry, taking into account the wagon's own oscillations — that is, replacing the attached-mass idealization of the source study with a coupled ferry–wagon dynamic model. Concretely, the required results are: (i) a coupled dynamic model in which the ferry's roll — excited, as in the source study, by trochoidal wave kinematics and wind loading on the above-water projection, under its hydrometeorological conditions and ferry parameters (Black Sea conditions, the Heroi Shipki-type train ferry fully loaded with 108 rail vehicles) — drives a wagon possessing its own degrees of freedom, comprising relative motion through its deck fastening (chain binders, support jacks, and the proposed viscous binder with activation above 5 tonnes and viscous resistance coefficient β\beta) together with elastic oscillation modes of the carrying structure coupled to the ship's roll, so that a model permitting only relative motion through the fastening, without coupling the carrying structure's elastic oscillation modes to the ship's roll, does not resolve component (i); (ii) the resulting accelerations on the wagon body and the maximum equivalent stresses in the carrying structure under both the typical fixation diagram and the viscous-binder fixation diagram; and (iii) a verdict on whether the strength and stability conclusions of the source line — admissibility of stresses, stability against capsizing on the deck, and the roughly 30% acceleration reduction attributed to the viscous binder — survive the coupled model. The single overarching objective uniting these components is a dynamic-load and strength determination for wagons transported by train ferries that no longer rests on the rigid-attached-mass idealization: component (i) supplies the load inputs for the strength assessment (ii), and both are prerequisites for judging the fixation schemes in (iii).

References

  1. Lovska, A.; Fomin, O.; Píštěk, V.; Kučera, P. Dynamic Load and Strength Determination of Carrying Structure of Wagons Transported by Ferries. Journal of Marine Science and Engineering 2020, 8(11), 902. DOI: 10.3390/jmse8110902; https://doi.org/10.3390/jmse8110902
  2. Lovska, A.; Gerlici, J.; Dižo, J.; Ishchuk, V. The Strength of Rail Vehicles Transported by a Ferry Considering the Influence of Sea Waves on Its Hull. Sensors 2024, 24(1), 183. DOI: 10.3390/s24010183; https://doi.org/10.3390/s24010183
  3. Gerlici, J.; Lovska, A.; Fomin, O.; Dižo, J.; Blatnický, M. Strength Analysis of an Open Car Body with Honeycomb Elements during Ro-Ro Transportation. Applied Sciences 2023, 13(19), 11022. DOI: 10.3390/app131911022; https://doi.org/10.3390/app131911022
  4. Lovska, A.; Gerlici, J.; Fomin, O.; Šťastniak, P.; Fomina, Y.; Kravchenko, K. Investigation of the Strength of a Chain Binder for Securing a Wagon on the Railway Ferry Deck. Communications – Scientific Letters of the University of Žilina 2023, 25(2), B130–B139. DOI: 10.26552/com.C.2023.037; https://doi.org/10.26552/com.C.2023.037
  5. Vatulia, G.; Gerlici, J.; Lovska, A.; Krasnokutskyi, Y.; Harušinec, J.; Šťastniak, P. Investigation Into the Dynamic Load of the Container with Sandwich Panel Walls when Transported by Train Ferry. TransNav – International Journal on Marine Navigation and Safety of Sea Transportation 2024, 18(1), 205–209. DOI: 10.12716/1001.18.01.21; https://doi.org/10.12716/1001.18.01.21
  6. Gerlici, J.; Vatulia, G.; Lovska, A.; Kravchenko, K.; Harušinec, J.; Suchánek, A. Determination Of The Loading On The Open Wagon Body When Rolling On The Train Ferry. TransNav – International Journal on Marine Navigation and Safety of Sea Transportation 2024, 18(3), 683–687. DOI: 10.12716/1001.18.03.23; https://doi.org/10.12716/1001.18.03.23
  7. Vatulia, G.; Lovska, A.; Myamlin, S.; Pavliuchenkov, M. Research into the loading of a removable module for transportation of long freight in a combined train by the train ferry. Bulletin of the National Technical University «KhPI», Series: Dynamics and Strength of Machines 2022, no. 1, 27–33. DOI: 10.20998/2078-9130.2022.1.264322; https://doi.org/10.20998/2078-9130.2022.1.264322
  8. Lovska, A.; Dižo, J.; Blatnický, M. Study of loading of a universal container during sea transport. Cognitive Sustainability 2025, 4(3). DOI: 10.55343/cogsust.20527; https://doi.org/10.55343/cogsust.20527
  9. Fomin, O.; Lovska, A.; Kulbovskyi, I.; Holub, H.; Kozarchuk, I.; Kharuta, V. Determining the dynamic loading on a semi-wagon when fixing it with a viscous coupling to a ferry deck. Eastern-European Journal of Enterprise Technologies 2019, 2/7(98), 6–12. DOI: 10.15587/1729-4061.2019.160456; https://doi.org/10.15587/1729-4061.2019.160456