Assessing the impact of small amounts of water and iron oxides on adhesion in the wheel/rail interface using High Pressure Torsion testing

Buckley-Johnstone, L.E.; Trummer, Gerald; Voltr, Petr; Meierhofer, Alexander; Six, Klaus; Fletcher, D. I.; Lewis, Roger

doi:10.1016/j.triboint.2019.02.024

Cited by 30 publications

(24 citation statements)

References 15 publications

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“…Twin disc experimental testing showed that friction decreased in a drying contact where there was a small amount of water mixed with oxides [10] (see Figure 1). Similar testing using a different type of test (High Pressure Torsion (HPT)) has shown similar effects [9] (see Figure 2). Here friction clearly dropped as the amount of water applied was reduced.…”

Section: Introductionmentioning

confidence: 74%

“…Looking at the timing of the incidents revealed that most wet-rail occurred during the morning and evening dew point, where a thin film of water would have been present on the rail head. Measurements on a rail head in an environment chamber have revealed that this amount was approximately 0.01 -0.68 µL per 100 mm 2 [9].…”

Section: Introductionmentioning

confidence: 99%

“…Neither, however, showed a drop to ultra-low adhesion conditions that would lead to braking problems (<0.05). Physical modelling of the HPT testing (see Figure 3) showed that it would be very difficult to achieve the exact conditions required for very low adhesion as only a small range of water/oxide mixture proportions leads to this occurring [9]. It was thought that it might be easier to study the mechanisms using a full-scale test approach.…”

Section: Introductionmentioning

confidence: 99%

“…Physical modelling of adhesion against water/oxide mixture proportion in HPT test interface for different amounts/heights (d) of water/oxide mixture[9] …”

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confidence: 99%

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Full-scale testing of low adhesion effects with small amounts of water in the wheel/rail interface

Buckley-Johnstone

Trummer

Voltr

et al. 2020

Tribology International

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Low adhesion in the wheel/rail contact can be caused by small amounts of water combining with iron oxides. This happens in light rain or at dew point. In small-scale tests, ultra-low adhesion (≤0.05) has not been maintained. The aim here was to see if the mechanism could be realized at a larger scale. Sustained ultra-low adhesion was achieved when water was applied constantly to the wheel/rail contact at a rate of 25µL/s. In these conditions wear debris and oxide was clearly visible in the contact band. Creep force data has been generated that can now be used to inform wheel/rail contact models and multi-body dynamics simulations of train behaviour with a view to developing mitigation.

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Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Physical modelling of adhesion against water/oxide mixture proportion in HPT test interface for different amounts/heights (d) of water/oxide mixture[9] …”

mentioning

confidence: 99%

See 2 more Smart Citations

Full-scale testing of low adhesion effects with small amounts of water in the wheel/rail interface

Buckley-Johnstone

Trummer

Voltr

et al. 2020

Tribology International

Self Cite

View full text Add to dashboard Cite

show abstract

“…Previous twin disc testing has simulated low adhesion due to leaf and oil contamination [12]. The influence of wear debris and iron oxides has been tested previously using twin disc testing and has produced lower traction than a "clean" specimen, as seen in Figure 2, but has not produced the very low traction seen when low adhesion incidents occur on the railway [4] [13]. Low adhesion due to an iron oxide layer has also been recreated using twin disc testing but this was at a low slip value of 0.3 %, which is typical for a rolling wheel but lower than would be seen when braking or accelerating [14].…”

Section: Year Leaf Contamination Reported No Leaf Contamination Reportedmentioning

confidence: 99%

Simulation and understanding the wet-rail phenomenon using twin disc testing

White

Lewis

2019

Tribology International

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Low adhesion due to the wet-rail phenomenon is a year round problem for the rail industry. It is thought to occur due to wear debris and iron oxides combined with small amounts of water, often from dew or light rain. It occurs without visible contamination and the transient, low moisture conditions mean that it has previously been difficult to study and has not been simulated in a laboratory, which limits understanding and inhibits the development of mitigation methods. This work simulates the wet-rail phenomenon on a twin disc test rig for the first time and concludes that iron oxide and water alone can form a paste and produce low traction values that are comparable to oil or leaf contamination.

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Iron Oxide and Water Paste Rheology and Its Effect on Low Adhesion in the Wheel/Rail Interface

et al. 2021

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The “wet-rail” phenomenon results in low adhesion between wheel and rail throughout the year, occurring transiently on a slightly wet, or drying railhead. It has been previously proposed that it is caused by a mixture of iron oxides and small amounts of water (from dew or precipitation) on the railhead that form a friction reducing paste. This paper outlines a novel combination of rheology, modelling and experimental work using a twin disc test rig to determine how the rheology of this iron oxide paste affects adhesion. The yield strength of different types of iron oxides, along with solid oxide fraction of the friction reducing paste, was assessed and used as an input into an “adhesion model” for assessing water and oxide suspensions. The rheological and modelling results were compared against very low adhesion recorded in twin disc experimental validation when simulating the wet-rail phenomenon.

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Assessing the impact of small amounts of water and iron oxides on adhesion in the wheel/rail interface using High Pressure Torsion testing

Cited by 30 publications

References 15 publications

Full-scale testing of low adhesion effects with small amounts of water in the wheel/rail interface

Full-scale testing of low adhesion effects with small amounts of water in the wheel/rail interface

Simulation and understanding the wet-rail phenomenon using twin disc testing

Iron Oxide and Water Paste Rheology and Its Effect on Low Adhesion in the Wheel/Rail Interface

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