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Keywords: heavy haul, operational conditions, load increase, track design.

Summary

During recent decades, as a result of the incremental demand for material transport, freight railways have developed cost effective strategies to increase loading capacity. Among these strategies, the increase of the vehicle axle load invokes a challenge for managers. The track can be technically unsuitable for the additional loads and stresses that are imposed. Except from certain guidelines, the heavy haul track structure design is based on the conventional project of a ballasted track. However, heavy haul type vehicles are characterized by a set of operational conditions (e.g. load, speed, traffic amount, etc.) which can differ significantly from the conventional freight and passenger service conditions. Basically, the general operational characteristics of heavy haul tracks are those: with a speed varying from 60 to 80 Km/h, loads higher than 25 tons/axle, using a large number of wagons, etc. In the context of a heavy haul track the higher axle loads may produce consequently higher stresses and deformations in the track components. The evaluation of the structural parameters values under a heavy haul scenario is of outstanding importance. The determination of loads and stresses acting in the railway components can provide a structural overview of a railway subjected to an extra loading.

This paper discusses the methodologies currently used in the railway structural design under a heavy haul perspective. Moreover, different methods for the calculation of the dynamic impact factors (DIF) are compared and evaluated. The stresses at both ballast and subgrade are determined under different operational conditions. The results showed a reasonable concordance between the methods for determining the DIF. Furthermore, the analysis showed that the higher influence of the load increase in the calculated stresses compared with the speed and geometry conditions within the range of values studied.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 110 PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON RAILWAY TECHNOLOGY: RESEARCH, DEVELOPMENT AND MAINTENANCE Edited by: J. Pombo Paper 226 Mechanical Analysis of a Heavy Haul Track under Different Operational Conditions J. Pires and A.G. Dumont Traffic Facilities Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland doi:10.4203/ccp.110.226 purchase the full-text of this paper Full Bibliographic Reference for this paper J. Pires, A.G. Dumont, "Mechanical Analysis of a Heavy Haul Track under Different Operational Conditions", in J. Pombo, (Editor), "Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance", Civil-Comp Press, Stirlingshire, UK, Paper 226, 2016. doi:10.4203/ccp.110.226 Keywords: heavy haul, operational conditions, load increase, track design. Summary During recent decades, as a result of the incremental demand for material transport, freight railways have developed cost effective strategies to increase loading capacity. Among these strategies, the increase of the vehicle axle load invokes a challenge for managers. The track can be technically unsuitable for the additional loads and stresses that are imposed. Except from certain guidelines, the heavy haul track structure design is based on the conventional project of a ballasted track. However, heavy haul type vehicles are characterized by a set of operational conditions (e.g. load, speed, traffic amount, etc.) which can differ significantly from the conventional freight and passenger service conditions. Basically, the general operational characteristics of heavy haul tracks are those: with a speed varying from 60 to 80 Km/h, loads higher than 25 tons/axle, using a large number of wagons, etc. In the context of a heavy haul track the higher axle loads may produce consequently higher stresses and deformations in the track components. The evaluation of the structural parameters values under a heavy haul scenario is of outstanding importance. The determination of loads and stresses acting in the railway components can provide a structural overview of a railway subjected to an extra loading. This paper discusses the methodologies currently used in the railway structural design under a heavy haul perspective. Moreover, different methods for the calculation of the dynamic impact factors (DIF) are compared and evaluated. The stresses at both ballast and subgrade are determined under different operational conditions. The results showed a reasonable concordance between the methods for determining the DIF. Furthermore, the analysis showed that the higher influence of the load increase in the calculated stresses compared with the speed and geometry conditions within the range of values studied. purchase the full-text of this paper (price £22) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £85 +P&P)
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