There is a 461-0xx series, that goes from 001 to 045, they are from around 1972., and were divided between ZTO Belgrade (461-001 to 461-024 or 025 plus 034) and ZTO Titograd, today's Podgorica (461-025 to 461-045), and a 461-1xx series (461-101 to 461-158, ZTO Belgrade, and ZTO Skopje). And in 2006. Končar from Zagreb, SR Croatia modernized some of them. Today they are the most numbered electric loco in Serbia, and used in Montenegro (the only electric loco they have) and FYR of Macedonia.