The process of traction-current asymmetry generation in rail lines

Abstract

The main sources of interference in automated devices and telemechanical devices at electrified railways are electric traction currents and harmonics thereof. On railways in Russia, such interference causes an average of 30 automatic locomotive signaling (ALS) failures every hour. The electrical and electromagnetic processes as a result of which such interference occurs are not understood. It remained unclear why the traction-current asymmetry in the rail line is a function of this current and is always greater than the asymmetry of resistances of these track rails. This paper presents some results of clarifying the causal factors involved. It is found that the primary cause of traction-current asymmetry in the rail lines is the emergence of asymmetry of resistances in the track rails. However, the asymmetry of the traction current is largely due to the emerging asymmetry of effective resistivities of mutual inductance of the track rails. It is also explained why the increase of traction current in the rails when heavy trains are in operation and in areas of traction substations does not lead to a proportional increase in the number of failures in the operation of rail electric circuits and automatic locomotive signaling.