The first 760 mm track-side diesel locomotives of the BDŽ were built by the German company Henschel & Sohn of Kassel, and were put into operation in Bulgaria in the beginning of 1966.

Moreover, due to the higher power of the locomotives, the trip from Septemvri to Dobrinishte was shortened by more than 1 hour.

The locomotives were constructed under the technical conditions of BDŽ and consisted mainly of: a diesel engine with a power of 1100 hp, a hydraulic gear and the wheelset formula is B'B'.

For the first time in Bulgaria the concept of using the cavities in the main locomotive frame for fuel tank was applied.

The first scrapped locomotive in the series was 75 007.5, which derailed on January 16, 1991, due to a broken track on the open line to the closed stop "Dryanov Dol".