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The article considers phenomenological and modelling approach to researching of interaction of a deformable wheel and a plane of support, their advantages and disadvantages are mentioned. In the context of phenomenological approach the five methods of locomotive tangent tractive force calculation were considered. There certainly must be pseudo-creeping to let locomotive tangent tractive force do work and change the kinetic energy of a train in the point of wheel and rail contact. Locomotive tractive force experts calculate the power as product of the locomotive tangent tractive force and the velocity of translational motion of a train, although in fact the velocity of the point of force application must be assumed. It is applied to a wheel pair, then the velocity of this point must be used to calculate the locomotive power. According to this fact the locomotive power is found several tens of times reduced.

The article sets out the methodology of the study of a rigid mathematical model describing locomotive wheel and rail interaction, taking into account the hypothesis f. Carter. On the basis of the application of the theorem N.A. Tikhonova derived the differential equation for determining the rate of slippage of wheel pair on Rails. Determine the time dependence for the establishment of a process of kinematic slippage of wheel pair on Rails from the wheel speeds and locomotive, from inertial characteristics of trains and the wheel, as well as the coefficient of creep, annexed to the torque of wheel pair and the State of the surfaces of the Rails.

As a result of tension increase and significantly loads on the overhead contact lines, there is need to research the tensile stress value for contact and messenger wires. In this paper, the author reviewed the wires operation conditions concerning the thermo-mechanical load. The author has analyzed the results of contact wires low-temperature creep tests. The real rate of contact wires creep is as appropriate as the standard values. At the same time, copper wire elongation is faster than bronze. The author has provided results about contact and messenger wires ultimate tensile stress tests, heated at different temperatures. The ultimate tensile stress rate for the copper and bronze contact wires is reducing by 9 % with temperatures increasing. The ultimate tensile stress rate for the cop-per messenger wires is reducing by 11 %, for the bronze wires - by 4 %, with rising temperatures to 150 °С. Test results have shown that heating of copper wires to temperatures above 90 °С and bronze wires to temperatures above 120 °С leads to a significant immediate reduction of strength. Working conditions for the overhead contact lines wires are close to the critical one. It is not sufficient for reliable and safe operation Author offers to modify regulatory requirements for contact and mes-senger wires concerning permissible heating and also not to divide short-term and long-term heat-ing and only to leave permissible heating.