Effect of Friction Modifier on Rolling Contact Fatigue and Wear of Wheel and Rail Materials

Rolling contact fatigue is a major problem connected with railway tracks, especially in curves, since it leads to higher maintenance costs. By optimising the top-of-rail friction, the wear and cracks on the top of the rail can eventually be reduced without causing very long braking distances. There are several research articles available on crack prediction, but most of the research is focused either on rail without a friction modifier or on wheels with and without friction control. In the present study, in order to predict the formation of surface-initiated rolling contact fatigue, a range of friction coefficients with different Kalker’s reduction factors has been assumed. Kalker’s reduction factor takes care of the basic tendency of creepage as a function of the traction forces at lower creepage. The assumed range covers possible friction values from those for non-lubricated rail to those for rail with a minimum measured friction control on the top of the rail using a friction modifier. A fatigue index model based on the shakedown theory was used to predict the generation of surface-initiated rolling contact fatigue. Simulations were performed using multi-body simulation, for which inputs were taken from the Iron Ore line in the north of Sweden. The effect of friction control was studied for different curve radii, ranging from 200 m to 3000 m, and for different axle loads from 30 to 40 tonnes at a constant train speed of 60 km/h. One example of a result is that a maximum friction coefficient (µ) of 0.2 with a Kalker’s reduction factor of 15% is needed in the case of trains with a heavy axle load to avoid crack formation.

Download Full-text

Influencing rolling contact fatigue through top of rail friction modifier application – A full scale wheel–rail test rig study

Wear ◽

10.1016/j.wear.2010.10.006 ◽

2011 ◽

Vol 271 (1-2) ◽

pp. 134-142 ◽

Cited By ~ 27

Author(s):

Richard Stock ◽

Donald T. Eadie ◽

Dave Elvidge ◽

Kevin Oldknow

Keyword(s):

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Full Scale ◽

Rolling Contact ◽

Test Rig ◽

Friction Modifier

Download Full-text

Carry distance of top-of-rail friction modifiers

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409718772981 ◽

2018 ◽

Vol 232 (10) ◽

pp. 2418-2430

Author(s):

Saad Ahmed Khan ◽

Jan Lundberg ◽

Christer Stenström

Keyword(s):

Coefficient Of Friction ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Third Body ◽

Friction Modifiers ◽

Friction Modifier ◽

Railway Traffic ◽

Railway Industry ◽

The Coefficient Of Friction

Rail issues such as corrugation, rolling contact fatigue, noise and wear have been increasing with the increase in railway traffic. The application of top-of-rail friction modifiers (TOR-FMs) is claimed by their manufacturers in the railway industry to be a well-established technique for resolving the above-mentioned issues. 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. TOR-FM manufacturers also claim that by using wayside equipment, the TOR-FM can be spread over a minimum distance of 3 km, over which it maintains a coefficient of friction of µ = 0.35 ± 0.05. To determine the carry distance of TOR-FMs, some researchers use tribometers to measure the coefficients of friction. However, moisture and deposits from the environment and trains can alter the top-of-rail friction and give a misleading indication of the presence of a friction modifier. Therefore, the coefficient of friction itself is not a clear indicator of the presence of TOR-FMs. In the present study, cotton swabs dipped in a mixture of alcohol and ester were used to collect surface deposits (a third body) from both the wheel and rail at various distances from the point of application. Subsequently, the third body collected on the cotton swab was analysed using an energy dispersive X-ray analysis. The results have shown that the maximum carry distance of TOR-FMs on the top of the rail is limited to 70 m when using a TOR-FM from one manufacturer and to 450 m when using a TOR-FM from another manufacturer. The carry distance on the contact band of the wheel is limited to 100 m and 340 m. The friction modifier on the edges of the contact band was detected over a distance of up to 3 km; however, this will not minimise the damage or friction at the wheel–rail interface.

Download Full-text

Friction management on a Chinese heavy haul coal line

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409712447170 ◽

2012 ◽

Vol 226 (6) ◽

pp. 630-640 ◽

Cited By ~ 9

Author(s):

Xin Lu ◽

Tony W Makowsky ◽

Donald T Eadie ◽

Kevin Oldknow ◽

Jilian Xue ◽

...

Keyword(s):

State Of The Art ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Friction Modifier ◽

Rail Wear ◽

Lateral Forces ◽

Heavy Haul ◽

The Impact ◽

Total Network

Shuohuang Railway (SHR) is one of the major coal carriers in China, with a total network length of 590 km running from Shenchi to Huanghua. Significant increases in annual operating tonnage have generated accelerated rail wear and rolling contact fatigue (RCF) growth problems for many sharper/lower radius curves. In order to address these rail problems, SHR is interested in the state-of-the-art total friction management (TFM) technology currently deployed by some North American heavy haul freight railroads and is evaluating the impact of TFM via a field trial at SHR’s Yuanping subdivision. This paper presents an evaluation of the effect of TFM, which includes both wayside gauge face lubrication and wayside application of a thin film top of rail friction modifier on control of lateral forces, rail wear and RCF.

Download Full-text

The effects of top of rail friction modifier on wear and rolling contact fatigue: Full-scale rail–wheel test rig evaluation, analysis and modelling

Wear ◽

10.1016/j.wear.2008.02.029 ◽

2008 ◽

Vol 265 (9-10) ◽

pp. 1222-1230 ◽

Cited By ~ 58

Author(s):

Donald T. Eadie ◽

Dave Elvidge ◽

Kevin Oldknow ◽

Richard Stock ◽

Peter Pointner ◽

...

Keyword(s):

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Full Scale ◽

Rolling Contact ◽

Test Rig ◽

Friction Modifier

Download Full-text

Effects of solid friction modifier on friction and rolling contact fatigue damage of wheel-rail surfaces

Friction ◽

10.1007/s40544-021-0521-5 ◽

2021 ◽

Author(s):

Jingdong Song ◽

Lubing Shi ◽

Haohao Ding ◽

Radovan Galas ◽

Milan Omasta ◽

...

Keyword(s):

Friction Coefficient ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Rolling Stock ◽

Friction Modifier ◽

Railway Network ◽

Wear Rates ◽

Subsurface Cracks ◽

Solid Friction

AbstractIn railway network, friction is an important factor to consider in terms of the service behaviors of wheel-rail system. The objective of this study was to investigate the effect of a solid friction modifier (FM) in a railway environment. This was achieved by studying the friction, wear, and rolling contact fatigue (RCF) damage on the wheel-rail materials at different slip ratios. The results showed that when a solid FM was applied, the friction coefficient decreased. After the solid FM was separated from the wheel-rail interface, the friction coefficient gradually increased to its original level. With the application of the solid FM, the wear rates of the wheel-rail decreased. In addition, the thickness and hardness of the plastic deformation layers of the wheel-rail materials were reduced. The worn surfaces of the wheel-rail were dominated by pits and RCF cracks. Without the FM, RCF cracks ranged from 84 to 120 µm, and subsurface cracks were generated. However, with the FM, RCF cracks ranged from 17 to 97 µm and no subsurface cracks were generated. These findings indicate possible methods of improving the performance of railway rolling stock by managing friction, and reducing wear and permanent RCF damage affecting both the wheels and rails.

Download Full-text