The development of a low creep regime, hand-operated tribometer

Harrison, H D

doi:10.1016/j.wear.2008.03.028

Cited by 15 publications

(11 citation statements)

References 2 publications

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“…Harrison 25 used this effect to investigate the influence of different contact pressures on the friction coefficient. The wheel is connected to a magnetic clutch and as the user commences a measurement, by pushing the device along the rail, the wheel rolls along the rail freely, i.e.…”

Section: Field Testsmentioning

confidence: 99%

A field test study of leaf contamination on railhead surfaces

Zhu

Olofsson

Nilsson

2012

Proceedings of the Institution of Mechanical Engineers, Part F:

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Leaves on railway tracks affect the level of adhesion between the wheel and rail, especially in autumn. When crushed by wheels, leaves form a tarnished, low level of adhesion layer that sticks to the railhead and often requires mechanical removal. A Stockholm local traffic track with a long history of adhesion problems was subjected to field tests on railhead contamination. On five occasions under different conditions, spaced over a year, the friction coefficient was measured using a tribometer and samples of the rail were taken. The techniques of electron spectroscopy for chemical analysis and glow discharge optical emission spectrometry were conducted to determine the composition of the top layer of rail contaminants and hardness was measured using the nano-indentation technique. The tarnished layer contains much higher contents of calcium, carbon and nitrogen than do leaf residue layers and uncontaminated samples. These high element contents are generated from the leaf material, which chemically reacts with the bulk material. The hardness of the tarnished layer is one-fifth that of the non-tarnished layer of the same running band. A chemical reaction occurs from the surface to a depth of several microns. The thickness of the friction-reducing oxide layer can be used to predict the friction coefficient and extent of leaf contamination.

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Section: Field Testsmentioning

confidence: 99%

A field test study of leaf contamination on railhead surfaces

Zhu

Olofsson

Nilsson

2012

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…In addition, the measurements in Colombia were done using a contact pressure of 1.1 GPa (TriboMetro FR-101 tribometer). The contact pressure of the Salient System tribometer used in the UK is around 0.7 GPa [3], and measurements with a lower contact pressure will report higher coefficients of friction (as seen in Figure 7 and [10]). This means that the values taken in the UK are higher than if tests had been done using the TriboMetro FR-101 tribometer.…”

Section: Field Test Resultsmentioning

confidence: 99%

Evaluation of the coefficient of friction of rail in the field and laboratory using several devices

Harmon

Santa

Jaramillo

et al. 2020

Tribology - Materials, Surfaces & Interfaces

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Accurate friction measurement is vital in order to apply appropriate friction management techniques to the wheel/rail interface. This work analyses different friction measurement techniques under a variety of conditions in the laboratory and the field. Tests have been carried out using a pendulum tester, hand-push tribometer, twin-disc machine, and full-scale rig in the UK and Colombia for a variety of interfacial conditions and rail hardness. The pendulum has been found to be more sensitive to different conditions than the hand-push tribometer. This is due to the area that the pendulum sweeps being smaller, and so it can be more carefully controlled and therefore measure the surface condition being tested. This is in contrast to the push tribometer which needs a long section of rail to take a measurement. Therefore, a small bit of contamination on one bit of rail will influence the results as the contamination will stay on the measuring wheel. Twin-disc and full-scale rig creep curves show good agreement between each other.

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“…The experience in heavy-haul traffic shows the ideal friction coefficient between the wheel and rail is high level over wheel tread and low level at wheel flange. [21] From this fact, the optmization region is chosen according to Equation (4) to obtain optimised adhesion level by optimising the wheel tread and reverse the flange part of the original profile. The optimisation problem (3) is solved by using the built-in function fminsearch in MATLAB, and the constraint Equation (4) is applied externally by fixing the boundary of the lateral coordinate of the wheel x in Equation (3).…”

Section: Optimisation Methodologymentioning

confidence: 99%

Design and optimisation of wheel–rail profiles for adhesion improvement

Liu

Mei

Bruni

2016

Vehicle System Dynamics

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This paper describes a study for the optimisation of the wheel profile in the wheel-rail system to increase the overall level of adhesion available at the contact interface, in particular to investigate how the wheel and rail profile combination may be designed to ensure the improved delivery of tractive/braking forces even in poor contact conditions. The research focuses on the geometric combination of both wheel and rail profiles to establish how the contact interface may be optimised to increase the adhesion level, but also to investigate how the change in the property of the contact mechanics at the wheel-rail interface may also lead to changes in the vehicle dynamic behaviour. ARTICLE HISTORY

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The development of a low creep regime, hand-operated tribometer

Cited by 15 publications

References 2 publications

A field test study of leaf contamination on railhead surfaces

A field test study of leaf contamination on railhead surfaces

Evaluation of the coefficient of friction of rail in the field and laboratory using several devices

Design and optimisation of wheel–rail profiles for adhesion improvement

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