DECREASE OF ROLLING RESISTANCE AND DAMAGEABILITY OF WHEELS AND RAILS IN CURVES

I. TUMANISHVILI, T. NADIRADZE, G. TUMANISHVILI
(Georgia)

Rolling resistance of wheel on a rail mainly depends on friction forces between a wheel and a rail. The energy loss due to friction of a wheel on a rail can reach about 24 % of full energy consumption on the traction [1] which is basically consumed on the overcoming of friction forces between wheels and rails especially in curves. For the heavy loaded frictional contact of wheels and rails, the variable values of friction forces, vibrations, noise and various kinds of destruction are characteristic. Therefore the control of friction between a wheel and a rail is necessary. Damage accumulation because of wear, fatigue and plastic deformation significantly reduces the service life of the railway wheels and rails. Therefore there are many works devoted to durability of wheels and rails and traffic safety [2-6 and references on their]. At the rolling of a wheel on a rail  the value of creepage and wear rate of wheels and rails considerably depend on geometry of working profiles, tribotechnical characteristics of wheels and rails and location of wheels relative to rails. In the present work the reasons of energy loss on a friction are considered and correction of a wheel profile for their reduction is offered.






EXPERIMENTAL RESEARCH INTO FRICTION MODIFIERS FOR THE TREAD, FLANGE AND GAUGE SURFACES OF WHEELS AND RAILS

G.I. TUMANISHVILI, M. TEDOSHVILI, V. ZVIADAURI, G.G. TUMANISHVILI
(Georgia)

The tread and the flange and gauge surfaces of wheels and rails require to have different properties – relative higher friction factor on tread surfaces and lower friction factor on flange and gauge surfaces and they needs corresponding friction modifiers. Adjustment of wear rate of wheels and rails, energy losses on friction, environment contaminations by vibration, noise and friction modifiers are considered as main functions of friction modifiers. In the present paper the ecologically friendly friction modifiers for tread and flange and gauge surfaces are tested in laboratory conditions on the twin disc machine. Experimentally are established  the ranges of variation of the friction factor of the friction modifiers accordingly for flanges 0.06–0.11 and for tread surfaces 0.12-0.4; The duration of the Single applied friction modifier was till 3000-12000 revolutions till its full removal from the interacting surfaces.