For investigating the pantograph discontact phenomena, this letter describes the statistical measurements of the discontact properties in the sliding-contacts. The current-dependences of the discontact and the discharge rates are elucidated.

This letter describes quantification measurements of the discontact phenomena appearing in the sliding-contacts. The inherent properties of the discontact phenomena are shown by statistically measuring the occurrence time-rates of the discontacts and the discharges.

This letter describes the occurrence-frequencies of the microarcs in the carbon sliding-contacts which are known to give the low radio-noises. A method is presented for statistically evaluating the arc occurrence-frequencies. The measurement results are also shown.