Possible reduction of wheel flange wear and occurrence of cracks on the axle-drives by improving electric-locomotive dynamic movement

Abstract

In this paper is analyzed negative influence on locomotive running dynamics, especially on the wheel flange wears and occurrence of cracks and fractures on the axle-drives, in the case when the contact between wheel and the rail is disturbed. This problem is especially expressed on railways with curved tracks. If the maintenance of tracks is poor, because of shortage of money for track maintenance, the attack angle between wheel and the rail becomes very large. With same unsprung masses and same locomotive speeds lateral forces between the wheel and rail increasing proportionate to the attack angle. These forces may be 2, 3 even 5 times larger then in normal conditions. In the case of rough tracks with the same coefficients of friction between the wheel flange and rail (dry or wet conditions) increasing the lateral forces between the wheel and rail lead to faster wheel flange wear. Contemporary, there were occurrence of cracks (more) and fractures (rarity) axle-driving shafts. To eliminate occurrence of cracks it is necessary, primarily, to shorten period of high rate of skidding locomotive wheels which appear in the case of traction heavy trains on the mountain lines. Same cause, track in bad conditions with greater tolerance of track width, have negative influence on riding stability and risk of derailment increasing. Also, with greater tolerance of track width we have faster wheel flange wears. As a result railway enterprises must reduce maximum speeds of vehicles if they want to satisfy all UIC requirements of riding stability or the risk of train derailment will be greater if they have not enough money for qualitative maintenance of tracks. For all this in the paper is given theoretical and experimental evidence.