The prototype of the series is built in 1966 at the
23 August plant in Bucharest (Romania). This locomotive is very similar in the undercarriage and bogie area to
Bm 4/4 diesel locomotive of the
Swiss Federal Railways (SBB CFF FFS).
The first tests took place until 1967, when the series production started. By 1992, when the last unit is delivered, a total of 1453x locomotives are built.
The
Romanian State Railways (CFR) buy a total of 633x units, initially registered
040-DHC-001 - 663. Later on, the locomotives from this series are divided in three classes:
Class 80 for standard gauge and equipped with a steam generator for passenger trains heating,
Class 81 for standard gauge and without a steam generator and
Class 84 for broad gauge railways in the eastern part of Romania.
476x units are acquired by Romanian industrial operators, registered from LDH125-001 to LDH125-480.
344x units are exported:
- 263x units to Bulgaria as
Class 55 for the
Bulgarian State Railways (BDZ) between 1968 and 1972;
- 42x units to Czechoslovakia as
Class 748.5 between 1972 and 1983;
- 32x units to Mozambique between 1980 and 1981 (these units are slightly shorter with 13000 mm in length, a different exterior design with a long, high hood on one side and a very short hood at the other end, separated by the cab, and a different gauge size: 1067 mm);
- 3x units to Iraq in 1984;
- 2x units to China in 1971;
- 1x unit to the USA in 1974;
- 1x unit to USSR in 1991.