2 September 2008 - Sofia, Chavdar bridge. Trolleybuses from the 29XX series usually run on line 9, but from time to time you may encounter them on other lines.Sofia, Chavdar bridge. Trolleybuses from the 29XX series usually run on line 9, but from time to time you may encounter them on other lines.София, моста \"Чавдар\". Autor: Balkanton