| 1. |
- Aggestam, Emil, 1992, et al.
(author)
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Innovative requirements and evaluation methods for slab track design
- 2024
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In: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 238:6, s. 651-661
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Journal article (peer-reviewed)abstract
- With increasing train speeds and reduced time windows for maintenance work, the interest in the application of slab track technology to increase the capacity of high-speed railways has grown. Slab track may still be considered a relatively young technology, but with several different designs available on the market. Current research on slab tracks commonly focuses on improved methods. In contrast, the formulation of requirements, and evaluation towards these, are seldom investigated. In this paper, state-of-the-art simulation models are employed to illustrate and address the needs for innovative requirements in terms of structural integrity and robustness, life cycle cost (LCC) and environmental footprint of new and existing slab track designs. Based on demonstration examples, it is argued that current standards may lead to overly conservative designs inducing higher LCC and environmental footprint than necessary. Extensions of the standards in terms of LCC and environmental footprint are suggested. The conflict of interest between structural integrity and robustness, LCC and environmental footprint is discussed, and suggestions for how to optimise slab track structures are proposed.
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| 2. |
- Anandika, Rayendra, 1988-, et al.
(author)
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Limitations of eddy current inspection for the characterization of near-surface cracks in railheads
- 2022
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 236:5, s. 532-544
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Journal article (peer-reviewed)abstract
- Eddy current (EC) testing is the most commonly used method to inspect near-surface cracks in railheads. Monitoring surface defects periodically is important to assess the track quality for serving daily operations. Nevertheless, despite being used in many countries, this method has limitations when characterizing cracks under the rail surface. Theoretically, EC testing is unreliable for the inspection of many cracks situated too close to each other in a concentrated location. This study has aimed to prove these limitations. EC signals from inspected cracks were compared with real crack profile parameters, i.e. depth and area, which were delivered by slicing the inspected cracked spots into 0.65 mm-thick pieces. The results show that the EC signal responses to the parameters of area and depth may lead to misleading measurements of the near-surface crack depth in the railhead. For instance, a shallower crack with a larger area can generate a higher EC signal response than a deeper crack with a smaller area. Another important conclusion is that the EC testing in this experiment could not be used to measure densely located cracks, which are those near-surface cracks which are typically found in a rail track.
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| 3. |
- Goodall, Roger, et al.
(author)
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An authorisation framework for actively controlled running gear
- 2022
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 236:9, s. 1070-1079
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Journal article (peer-reviewed)abstract
- A Shift2Rail funded research project called RUN2Rail has investigated a range of new technologies for railway rolling stock. The project included a task on the use of active suspensions, and one of the subtasks was to propose a strategy supporting the authorisation by safety authorities for highly innovative mechatronic vehicles to be placed on the market. The incorporation of electronics and control into suspension systems is still at an early stage, so this paper provides a framework for a practical and efficient authorisation strategy, primarily based upon existing European regulations and standards but in general applicable worldwide.
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| 4. |
- Kabo, Elena, 1972, et al.
(author)
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Characterisation of track buckling resistance
- 2024
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In: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; in Press
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Journal article (peer-reviewed)abstract
- This study sets out with a network-wide analysis of the risk for track buckling that concludes that track buckling relates to a few “weak points” along the track. To identify these, a numerical model to predict track buckling resistance is developed. The influences of key track parameters are evaluated and quantified using the innovative concept of an equivalent temperature. This allows to quantify the large influence of for example, curves and hanging sleepers in terms of an equivalent increase in temperature. Influence of less well-defined track parameters such as nearby fixed points or recent track work is estimated through statistical assessment of track buckling reports. Predicted influence generally agrees with empirical knowledge with some exceptions that are discussed in the report. Developed models and produced results should be valuable in identifying track sections at risk of track buckling and in assessing effectiveness of mitigating actions.
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| 5. |
- Khan, Saad Ahmed, 1987-, et al.
(author)
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Life cycle cost analysis for the top-of-rail friction-modifier application : A case study from the Swedish iron ore line
- 2021
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 235:1, s. 83-93
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Journal article (peer-reviewed)abstract
- The application of top-of-rail friction modifiers (TOR-FMs) is claimed by their manufacturers as a well-established technique for minimising the damages in the wheel–rail interface. There are various methods for applying friction modifiers at the wheel–rail interface, among which stationary wayside systems are recommended by TOR-FM manufacturers when a distance of a few kilometres is to be covered. An on-board system is recommended when an area of many kilometres has to be covered and focus is more on particular trains. Trafikverket in Sweden is considering the implementation of the TOR-FM technology on the iron ore line. Directly implementing such technology can be inappropriate and expensive, because the life cycle cost of a TOR-FM system has never been assessed for the conditions of the iron ore line. In the present study, the life cycle cost is calculated for wayside and on-board application systems, by taking inputs from the research performed on iron ore line. The present research has taken the iron ore line as a case study, but the results will be applicable to other infrastructure with similar conditions. The results have shown that the wayside equipment is economically unfeasible for the iron ore line. In this case, the life cycle cost increases by 4% when the friction modifier is applied on all curves with a radius smaller than 550 m and by 19% when the friction modifier is applied on all curves with a radius smaller than 850 m. The on-board system used in this study is shown to be economically feasible, as it has a significantly lower operation and maintenance cost than the wayside equipment. The reduction in the maintenance (grinding and rail replacement) cost when the cost of the friction modifier application is added is 27% when the friction modifier is applied on curves with a radius smaller than 550 m and 23% when the friction modifier is applied on curves with a radius smaller than 850 m.
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| 6. |
- Khan, Saad Ahmed, 1987-, et al.
(author)
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The effect of third bodies on wear and friction at the wheel-rail interface
- 2022
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 236:6, s. 662-671
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Journal article (peer-reviewed)abstract
- The friction forces between the wheel and rail depend on a number of variables including the third body layer at the wheel–rail interface, the wheel and rail profiles, and the train dynamics. The third body layer significantly influences the damage mechanisms at the wheel-rail interface, especially wear, rolling contact fatigue (RCF), corrugations and other surface defects that then require maintenance. The introduction of additional constituents at the wheel–rail interface in the form of an additive with anti-wear and anti-crack properties can reduce the wear and RCF. In general, such an additive also reduces the friction. However, it is important to avoid the friction coefficient between the wheel tread and the top of the rail falling below 0.3 because the result would be wheel slip and long braking distances. Measuring friction coefficients accurately is still a challenge, as most existing tribometers are unable to replicate the wheel-rail contact conditions, specifically the contact pressure and sliding speed. The present study used a newly designed handheld tribometer that is able to match the typical contact pressure. Results obtained with the handheld tribometer have been compared with values extracted from the traction-force measurement system of a locomotive. The tribometer field measurements have shown that by using a top-of-rail friction modifier (TOR-FM), both the wear and the friction coefficients can be reduced, but also that heavy TOR-FM films may cause unacceptably low friction. Comparing the results of field and laboratory tests confirms that weather and realistic third bodies present on the track have a significant effect on friction and wear. © IMechE 2021.
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| 7. |
- Kour, Ravdeep, 1981-, et al.
(author)
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A review on cybersecurity in railways
- 2022
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017.
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Research review (peer-reviewed)abstract
- Digitalisation is transforming the railway globally. One of the major considerations in digital transformation of any industry including the railway is the increased exposure to cyberattacks. The railway industry is vulnerable to these attacks because since the number of digital items and also number of interfaces between digital and physical components in the railway systems keep increasing. Increased number of items and interfaces require new frameworks, concepts and architectures to ensure the railway system’s resilience with respect to cybersecurity challenges, such as lack of proactiveness, lack of holistic perspective and obsolescence of safety systems exposed to current and future cyber threats landscape. To this date, there are several works carried out in the literature that studied the cybersecurity aspects and its application on railway infrastructure. However, to develop and implement an appropriate roadmap to cybersecurity in railways, there is a need of describing emerging challenges, and approaches to deal with these challenges and the possibilities and benefits of these.Hence, the objective of this paper is to provide a systematic review and outline cybersecurity emerging trends and approaches, and also to identify possible solutions by querying literature, academic and industrial, for future directions. The authors of this paper conducted separate searches through four popular databases, that is, Google Scholar, Scopus, Web of Science and IEEE explore. For the screening process, authors have used keywords with Boolean operators and database filters and identified 90 articles most relevant to the study domain. The analysis of 90 articles shows that majority of the cybersecurity studies lies within the railways are conceptual and lags in application of Artificial Intelligence (AI) based security. Like other industries, it is very important that railways should also follow latest security technologies, trends and train their workforce for cyber hygiene since railways are already in digitalization transition mode.
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| 8. |
- Kour, Ravdeep, 1981-, et al.
(author)
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Cybersecurity for railways : A maturity model
- 2020
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 234:10, s. 1129-1148
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Journal article (peer-reviewed)abstract
- With the advancements in and widespread adoption of information and communication technologies in infrastructures, cyber-attacks are becoming more frequent and more severe. Advanced cybersecurity threats with automated capabilities are increasing in such sectors as finance, health, grid, retail, government, telecommunications, transportation, etc. Cyber-attacks are also increasing in railways with an impact on railway stakeholders, e.g. threat to the safety of employees, passengers, or the public in general; loss of sensitive railway information; reputational damage; monetary loss; erroneous decisions; loss of dependability, etc. There is a need to move towards advanced security analytics and automation to identify, respond to, and prevent such security breaches. The objective of this research is to reduce cyber risks and vulnerabilities and to improve the cybersecurity capabilities of railways by evaluating their cybersecurity maturity levels and making recommendations for improvements. After assessing various cybersecurity maturity models, the Cybersecurity Capability Maturity Model (C2M2) was selected to assess the cybersecurity capabilities of railway organizations. The contributions of this research are as follows. First, a new maturity level MIL4 (Maturity Indicator Level 4) is introduced in the C2M2 model. Second, the C2M2 model is adapted by adding advanced security analytics and threat intelligence to develop the Railway-Cybersecurity Capability Maturity Model (R-C2M2). The cybersecurity maturity of three railway organizations is evaluated using this model. Third, recommendations and available standards & guidelines are provided to the three railway organizations to improve maturity levels within different domains. In addition, they are given an action plan to implement the recommendations in a streamlined way. The application of this model will allow railway organizations to improve their capability to reduce the impacts of cyber-attacks and eradicate vulnerabilities. The approach can also be extended to other infrastructures with necessary adaptations.
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| 9. |
- Krishna, Visakh V, et al.
(author)
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An integrated numerical framework to investigate the running safety of overlong freight trains
- 2020
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017.
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Journal article (peer-reviewed)abstract
- Long freight trains up to 1500 m in length are currently not in regular operation in Europe. One of the important reasons for the same is high inter-wagon forces generated during the operation, especially when pneumatic (P-type) brake systems are used. For long trains with multiple locomotives at different positions along the train, radio communication with necessary fail-safe mechanisms can be used to apply the brakes. Long freight train operation on a given line is subjected to various attributes such as braking/traction scenarios, loading patterns, wagon geometries, brake-block materials, buffer types, track design geometries, etc., which are referred to as heterogeneities. The complex longitudinal train dynamics arising in the train due to various heterogeneities play a major role in determining its running safety. In this context, the maximum in-train force refers to the maximum force developed between any two wagons along the train during operation. The tolerable longitudinal compressive force is the maximum compressive force that can be exerted on a wagon without resulting in its derailment. Here, the authors adopt a bottom-up approach to model pneumatic braking systems and inter-wagon interactions in multibody simulation environments to study the complex longitudinal train dynamics behavior and estimate maximum in-train forces and tolerable longitudinal compressive forces, subjected to various heterogeneities. These two force quantities intend to facilitate a given freight train operation by providing guidelines regarding the critical heterogeneities, that currently limit its safe operation. In doing so, the authors propose the notion to have an operation-based approval for long freight trains using the simulations-based tool.
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| 10. |
- Krishna, Visakh V, et al.
(author)
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Tolerable longitudinal forces for freight trains in tight S-curves using three-dimensional multi-body simulations
- 2020
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 234:5, s. 454-467
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Journal article (peer-reviewed)abstract
- With the need for increasing length of freight trains, Longitudinal Train Dynamics (LTD) and its influence on the running safety becomes a key issue. LTD is a complex issue with contributions from both the vehicles and the operating conditions such as infrastructure design, braking regimes, etc. Standards such as the UIC Code 530-2 and EN-15839 detail the procedure for on-track propelling tests that should be conducted to determine the running safety of a single wagon. Also, it only considers a single S-curve and specifies neighbouring wagons and buffers. The resulting LTD would hence not be able to judge the effects of various heterogeneities in the train formation such as the adjacent wagons, buffer types, carbody torsional stiffnesses, curvatures, etc. Here, there is a potential of using three-dimensional multi-body simulations to develop a methodology to judge the running safety of a train with regards to its longitudinal dynamic behaviour, subjected to various heterogeneities. A tool based on three-dimensional multi-body simulations has been developed to provide Longitudinal Compressive Force (LCF) limits, tolerable LCF for wagon combinations passing through S-curves of varying curvatures and assess the sensitivities of the various heterogeneities present in the train. The methodology is applied to open wagons of the ‘Falns’ type on tight S-curves by calculating the corresponding tolerable LCF and the effect of various parameters on the same is discussed.
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