Approaches to determining the required fastening temperature of continuously welded rail (CWR) track

Continuously welded rail (CWR) is the primary and most advanced design for railway superstructure, with its annual installation mileage increasing due to significant advantages over jointed track. These benefits include the elimination of impact loads and track disorders at joints, extended service life for both superstructure components and rolling stock, noise reduction, decreased train running resistance, and others. When strict temperature regimes are observed, CWR proves to be more efficient, easier to maintain, and safer than jointed track. Currently, a temperature-stressed CWR structure is universally employed, where rails are fastened for permanent operation without seasonal re-fastening. Consequently, the question of how to correctly determine the required temperature for anchoring rail strings has always been and remains relevant. Longitudinal forces and stresses arising from temperature fluctuations relative to the rail fastening temperature reach high values in summer and winter, posing a threat of buckling or fracture of the rail strings.

The objective of this work is to analyze methods for determining the optimal temperature range for fastening rail strings currently used on Russian Railways as well as on railways worldwide, aiming to minimize risks associated with high longitudinal thermal forces.

Both stability theory and long-term practice in the construction and maintenance of continuous track indicate that the higher the rail string fastening temperature, the lower the probability of its instability (buckling), and vice versa: the probability of fracture increases during the winter period. Since the loss of stability is considered a more hazardous event than fracture, it is common practice on Russian Railways and in many other countries to fasten rails at higher temperatures. Annual efforts are being made to improve the quality of rail steel, whose tensile strength currently exceeds 800 MPa. However, beyond the strength of the rail itself, the durability of bolted joint connections at turnout approaches must also be taken into account. To prevent shear failure of fishplate bolts during lowtemperature exposure, the paper proposes the seasonal re-fastening of 200-meter ends of long and extra-long rail strings (extending up to a signaling block section or an entire line section). A more radical solution to ensure the integrity of joint bolts in winter is the direct welding of rail strings to turnouts.

1. Instructions for the installation, installation, maintenance and repair of a continuously welded track. Approved by the Order of Russian Railways dated 14.12.2016 Nо. 2544r. Moscow: Tsentrmag; 2025. 176 p. (In Russ.).

2. Kornienko E. V. Features of the stress-strain state of a continuously welded track when taking into account the effects of trains. Specialty 05.22.06 ‘Railway track, railway survey and design: dissertation for the degree of Candidate of Engineering; Rostov State Transport University. Rostov-on-Don; 2019. 145 p. (In Russ.).

3. Technical instructions for the installation, installation, maintenance and repair of a continuously welded track. Moscow: Transport; 2000. 96 p. (In Russ.).

4. TB 10015-2012. The industry standard of the People's Republic of China. The construction of a continuously welded track. Beijing: Chinese Railway Publishing House; 2013. 130 p. (In Russ.).

5. Saltan Mehmet, Ferhat Çeçen, Ömer Faruk Acar. Rail Thermal Buckling Risk Management: Comparative Analysis of Stress-Free Temperature Determination in the USA and Türkiye. 2nd International Symposium on Innovations in Civil Engineering and Technology (ICivilTech 2024) At: Isparta/Türkiye. 2024. URL: https://www.researchgate.net/publication/387655523_Rail_Thermal_Buckling_Risk_Management_Comparative_Ana lysis_of_Stress-Free_Temperature_Determination_in_the_USA_and_Turkiye.

6. AREMA. Stand for Track. American Railway Engineering and Maintenance-of-Way Association. URL: https://www.railroadfasteners.com/download/AREMA-Stand-for-Track.pdf.

7. APTA RT-FS-S-002-02, Rev. 1. Standard American Public Transportation Association 1300 I Street, NW, Suite 1200 East, Washington, DC 20006 First Published: Sept. 22, 2002. First Revision: April 7, 2017. URL: https://www.apta.com/wp-content/uploads/Standards_Documents/APTA-RT-FS-S-002-02-Rev-1.pdf.

8. Novakovich V. I., Zalavsky N. I., Karpachevsky G. V. [et al.]. Stability of the track is the main condition for traffic safety. Track and Track Facilities. 2026;(3):22–25. (In Russ.).

9. Novakovich V. I., Karpachevsky G. V., Zalavsky N. I. [et al.]. On the justification of the established temperature regime of a continuously welded track. Track and Track Facilities. 2022;(6):38–40. (In Russ.).

10. Novakovich V. I., Karpachevsky G. V., Zalavsky N. I. [et al.] To revise the instructions for the installation, laying, maintenance and repair of a continuously welded track. Track and Track Facilities. 2023;(8):32–33. (In Russ.).

11. Novakovich V. I., Karpachevsky G. V., Zalavsky N. I. Justification of the established temperature regime for the operation of a continuously welded track. Actual Problems and Prospects for the Development of Transport, Industry and the Economy of Russia (TransPromEk-2024). Proceedings of the International Scientific and Practical Conference dedicated to the 95th anniversary of the Rostov State Transport University. Rostov-on-Don; 2024. P. 197–200. (In Russ.).

12. Suslov O. A. Functional continuously welded track safety operation. Specialty 05.22.06 ‘Railway track, survey and design of railways’: dissertation for the degree of Doctor of Engineering; Scientific Research Institute of Railway Transport. Moscow; 2017. 241 p. (In Russ.).

13. Assessment of pathway release risk. Railways of the World. 2006;(8):76–78. (In Russ.).

14. Ferhat Çeçen, Bekir Aktaş. Ray Sıcaklığı Takip Sistemleri (RSTS) için En Uygun Yerlerin Belirlenmesinde Termal Kameralardan Yararlanılması: Hızlı Analiz Metotları Geliştirilmesi. Demiryolu Mühendisliği. 2024. URL: https://www.researchgate.net/publication/382298263_Ray_Sicakligi_Takip_Sistemleri_RSTS_icin_En_Uygun_Yerle rin_Belirlenmesinde_Termal_Kameralardan_Yararlanilmasi_Hizli_Analiz_Metotlari_Gelistirilmesi_Use_of_Thermal _Imaging_Cameras_to_Identify_Best_Loca.

15. Ferranti Emma, Chapman Lee, Lowe Caroline, McCulloch Steve, Jaroszweski David, Quinn Andrew. HeatRelated Failures on Southeast England’s Railway Network: Insights and Implications for Heat Risk Management. Weather, Climate, and Society. 2016. URL: https://www.researchgate.net/publication/294723085_ Heat-Related_Failures_on_Southeast_England's_Railway_Network_Insights_and_Implications_for_Heat_Risk_ Management.

16. Dobney K., Baker C., Quinn Andrew, Chapman Lee. Quantifying the effects of high summer temperatures due to climate change on buckling and rail related delays in south-east United Kingdom. Meteorological Applications. 2009. URL: https://www.researchgate.net/publication/230320048_Quantifying_the_effects_of_high_summer_temperatures_ due_to_climate_change_on_buckling_and_rail_related_delays_in_south-east_United_Kingdom.

17. Palin Erika, Thornton Hazel, Mathison Camilla [et al.]. Future projections of temperature-related climate change impacts on the railway network of Great Britain. Climatic Change. 2013. URL: https://www.researchgate.net/publication/ 257548222_Future_projections_of_temperature-related_climate_change_impacts_on_the_railway_network_of_Great_ Britain.

18. Villalba Ignacio, Franco Ricardo, Salvador Zuriaga, Pablo Martínez Fernández. Risk of increasing temperature due to climate change on operation of the Spanish rail network. Transportation Research Procedia. 2020. URL: https://www.researchgate.net/publication/340072112_Risk_of_increasing_temperature_due_to_climate_change_on_ operation_of_the_Spanish_rail_network.