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.
- wheel arrangement: B'-B';
- length over buffers: 13700 mm;
- height over cab: 4650 mm;
- height over long hood: 3750 mm;
- distance between bogie pivots: 7200 mm;
- distance between axle centers: 2500 mm;
- weight: 70 - 72 t;
- axle loading: 17.5 - 18 t;
- fuel tank capacity: 3000 l;
- Sulzer 6LDA28B diesel engine;
- Voith TH2 hydraulic transmission;
- power: 920 kW (1250 hp);
- traction force: 231 kN;
- maximum speed: 100 km/h.
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.