The section between Maibara and Nagahama of the Hokuriku Main Line was added to the Biwako Line when the section between Tamura Station and Nagahama was changed from AC electrification to DC electrification in September 1991; however, the same line between Nagahama and Tsuruga Station, which was changed to DC electrification in October 2006, was not added to the Biwako Line.
北陸本線の米原～長浜間は、1991年9月に田村駅～長浜間が交流電化から直流電化に変更された際に琵琶湖線に加えられたが、2006年10月に直流電化に変更された同線の長浜～敦賀駅間は琵琶湖線に加えられていない。