Review of top of rail friction modifier tribology

Harmon, Matthew; Lewis, Roger

doi:10.1080/17515831.2016.1216265

Cited by 44 publications

(42 citation statements)

References 67 publications

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“…The citations used for this review have been graded to visualise the research area and determine which research has been carried out and what published research is lacking, using the same evaluation method as used in [69].…”

Section: Paper Gradingmentioning

confidence: 99%

The low adhesion problem due to leaf contamination in the wheel/rail contact: Bonding and low adhesion mechanisms

Ishizaka

Lewis

2017

Wear

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Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00 -10:00 and 20:00 -24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for bonding mechanisms and low adhesion mechanisms were proposed, such as sub-or super critical water and pectin gel.

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Section: Paper Gradingmentioning

confidence: 99%

The low adhesion problem due to leaf contamination in the wheel/rail contact: Bonding and low adhesion mechanisms

Ishizaka

Lewis

2017

Wear

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“… A wide variety of friction modifiers and friction enhancers are available in the market today, and the choice of specific coating material will be highly dependent on the nature of railway operations and track conditions.  In case of high-friction contacts, lubrications in the boundary regime, mixed lubrication or hydrodynamic lubrication are applied on the basis of Stribeck curve, adopting the optimum friction coefficients for avoiding rolling contact fatigue and high rates of wear due to plastic deformations [4]. …”

Section: Discussionmentioning

confidence: 99%

Influence of train axle load on wheel-rail interface friction

Khan

Dasaka

2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The implementation of high speed railways in India are in their early phases and vast studies are being conducted for the effective implementation of the system. Maintaining the traction required for efficient operation of trains at high speeds requires the net minimum frictional coefficient to be maintained at the wheel-rail interface, across the desired range of axle loads and target speeds of train operation. With the increase in speed, wheels of the train tend to lift-off, effectively reducing the interface friction at the wheel-rail contact. In this study, the effect of increasing the axle load on the effective frictional coefficient available at wheelrail interfaces during high speed railway operations were quantified by numerical simulations, and the results reveal that the net frictional coefficient available at the wheel-rail contacts have a trend to increase with an increase in the applied axle loads. Conversely, this instead points out that decreasing the axle loads for achieving higher speeds of train operation will result in reduction of traction, and there will be chances of wheel-slips on the rails during rapid acceleration and emergency braking situations. Modifying the rail surface friction using top-ofrail friction modifiers are a much easier alternative to making amendments in the wheel-rail profiles, for maintaining sufficient traction on rails. In the wheel-rail interfaces with high friction, lubrications in the boundary regime, mixed lubrication or hydrodynamic lubrication are applied on the basis of Stribeck curve, adopting the optimum frictional coefficients for avoiding rolling contact fatigue and high rates of wear due to plastic deformations. When there is less frictional grip, a coating of top-of-rail positive friction enhancers becomes necessary, for increasing the adhesion characteristics and achieving positive creep. This study emphasizes the importance of optimizing the contact at wheel-rail interfaces, to maintain the frictional coefficients to neither cause loss of traction due to lower grip, nor be on the higher side to cause rolling contact fatigue and high rates of material wear.

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“…The method used to evaluate the quality of each study is given in Table 1. Although other methods have been developed for grading work in tribology [11] these have not been used in favour of more simple and objective measures.…”

Section: Criteriamentioning

confidence: 99%

An analysis of the quality of experimental design and reliability of results in tribology research

Watson

Christoforou

Herrera

et al. 2019

Wear

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In recent years several high profile projects have questioned the repeatability and validity of scientific research in the fields of psychology and medicine. In general, these studies have shown or estimated that less than 50% of published research findings are true or replicable even when no breaches of ethics are made. This high percentage stems from widespread poor study design; either through the use of underpowered studies or designs that allow the introduction of bias into the results. In this work, we have aimed to assess, for the first time, the prevalence of good study design in the field of tribology. A set of simple criteria for factors such as randomisation, blinding, use of control and repeated tests has been made. These criteria have been used in a mass review of the output of five

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Review of top of rail friction modifier tribology

Cited by 44 publications

References 67 publications

The low adhesion problem due to leaf contamination in the wheel/rail contact: Bonding and low adhesion mechanisms

The low adhesion problem due to leaf contamination in the wheel/rail contact: Bonding and low adhesion mechanisms

Influence of train axle load on wheel-rail interface friction

An analysis of the quality of experimental design and reliability of results in tribology research

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