The influence of unloaded rails on the distribution of switch tie deflection in connecting tracks

The paper presents the findings of a study exploring the influence of unloaded rails in connecting tracks on the distribution of deflection of reinforced concrete switch ties when a train moves along the direct track. The finite element method (FEM) was used to develop a spatial analytic model of connecting tracks at a turnover, including both loaded and unloaded rails and switch ties on a continuous elastic cushion. The model was verified by comparing the FEM calculations against the conventional solution for a beam on an elastic cusion using the initial parameter method (Krylov functions). The comparison of results has shown good convergence. The study has identified quantitative relationships between changes in system stiffness and distribution of deflections along the switch tie length based on its length and loading patterns. It has been shown that unloaded rails reduce the maximum deflection by 5–15%, displace the deflection point towards the centre of the switch tie, and contribute to more uniform distribution of deflection. When unloaded rails are excluded from the calculation, the load transfer efficiency factor for switch tie-to-ballast load transfer is overestimated. The “reverse” bending of the switch tie ends typical of the design model of a beam on a continuous elastic cushion remains virtually unchanged when unloaded rails are introduced. This value is mainly determined by the length of a switch tie and stiffness of the cushion, which supports and elaborates on the conventional approaches offered by V.F. Yakovlev and I.I. Semenov.

1. Voloshko Y.D., Orlovsky A.N. How turnouts work under trains. Moscow. Transport. 1987:120. (In Russ.).

2. Glyuzberg B.E., Titarenko M.I., Korolev V.V. Main causes of failures of rail elements of turnouts. In: Improving the quality and operating conditions of rails and rail fastenings: Collection of scientific reports based on the materials of the meeting of the non-commercial partnership “Rail Commission”, Yekaterinburg, 23–25 October 2012. Yekaterinburg. OAO “UIM”. 2013:176-187. EDN: MEMKKM. (In Russ.).

3. Glyuzberg B.E. Modernization and improvement of turnouts. Railway transport. 2015;(7):54-57. EDN: UDLPFP. (In Russ.).

4. Glyuzberg B.E. Prospects for the development of turnout products for Russian railways. Implementation of modern designs and advanced technologies in track facilities. 2015;8(8):34-38. EDN: WEOJIR. (In Russ.).

5. Glyuzberg B.E., Titarenko M.I., Korolev V.V. Rail elements of turnouts. Railway transport. 2013;(11):44-46. EDN: RELLLF. (In Russ.).

6. Glyuzberg B.E. Application of optimization algorithms to improve the design of turnouts. Vniizht Bulletin (Railway Research Institute Bulletin). 2016;75(2):67-73. EDN: VXQARR. (In Russ.).

7. Dalzel G. New turnout designs in Great Britain. Railways of the World. 2007;(2):74-77. (In Russ.).

8. Blazhko L.S., Zakharov V.B., Chernyaev E.V., Shekhtman E.I. Extending the service life of turnouts through non-uniform stiffness of rail threads in the turnout curve and building a traffic safety management system in a railway company considering economic factors. Bulletin of scientific research results. 2017;(4):7-14. EDN: TGGMGF. (In Russ.).

9. Egorov M.A. Design-technological and organizational measures to improve the stability of track geometry at turnouts [dissertation]. 2017:250. EDN: UZGITW.

10. Ermakov V.M., Egorov M.A. Dynamic simulation of the interaction between turnouts and rolling stock. Railway Transport. 2016;(8):64-66. EDN: WIAANL. (In Russ.).

11. Romen Yu.S., Glyuzberg B.E., Timakova E.A., Bykov V.A. Features of mathematical modeling of dynamic processes of car passing railroad turnouts. Russian railway science journal. 2020;79(3):119-126. DOI: 10.21780/2223-9731-2020-79-3-119-126. EDN: HKJVRW. (In Russ.).

12. Nefedova E.V., Epishko E.S. Calculation of turnout stresses by modeling in SolidWorks. Science and youth of the XXI century. Materials of the VI Scientific and Technical Conference (Novosibirsk, 29 October – 2 November 2007). Novosibirsk. SGUPS Publishing House. 2008:33-34. (In Russ.).

13. Yakovlev V.F. Some issues of static calculation of turnout elements [abstract of dissertation]. Leningrad: Leningrad Order of Lenin Institute of Railway Engineers named after Academician V.N. Obraztsov; 1955:16. (In Russ.).

14. Semenov I.I. On elastic irregularities of rail threads within turnouts. Turnouts for high-speed train operations. Collection of works. Issue 21. Ed. S.V. Amelin. Leningrad. 1963:158-180. (In Russ.).

15. Gorbunov-Posadov M.I. Beams and slabs on elastic foundation. Moscow. Mashstroyizdat. 1949:239. EDN: USXQSY. (In Russ.).

16. Lysyuk V.S., Sazonov V.N., Bashkatova L.V. Strong and reliable railway track. Moscow. Akademkniga. 2003. EDN: QNQVKN. (In Russ.).