Results of apparent resistivity curves calculations of the stray current prospecting method of electric railway stray current for a case infinitely long, uniformly earthed, unbranching tracks lying on horizontally homogeneous layered geoelectric section are presented, at the various combinations of typical parameters of railroad tracks directly influencing spatial structure of the field used in a method. Deviation limits of the mentioned parameters from the true values are established. It allows to obtain reliable values pk,mc almost on all practically significant survey profile segment.