44-081 at the mountain station Vakarel most likely waiting to be called as the assisting locomotive for passing freight trains. This part of the Sofia-Plovdiv line, which is a part of the Turkey-Serbia corridor, runs steeply up- and downhill and many freight trains need helper locomotives that shuttle around it and help the numerous freight trains passing there daily. Another locomotive (46-208) is parked behind, most likely for the same purpose.

Photo by A. B. Kantchev (assenkantchev@yahoo.com)