This series is originally based on the license of the Swedish company ASEA. The 30 electric locomotives originally from series 441 of Serbian Railways have been modified by Končar Group from Zagreb, Croatia and MIN (Mašinska Industrija Niš) from Niš, Serbia. First modified locomotive, that received new code number - ŽS series 444 (former 441-077), has become operational in sumer 2004. Last modified locomotive was opened to traffic in January 2007. The modification is based on the restoration of 441 series.