The older lines in the west of the Oslo T-bane system were built with overhead lines while the eastern lines were built with third rail, although the entire system has since been converted to third rail.
Jalur yang lebih tua di barat Oslo T-bane dibangun dengan sistem listrik aliran atas, sedangkan jalur di timurnya dibangun dengan rel ketiga, meskipun seluruh sistem sejak itu telah dikonversi ke rel ketiga.