CFU 29 belongs to a series they designed to be used on the inner railroads (the Plant Industrial Railroads) and other railroads especially for hard transports in iron works.

Only 7 engines of that type were manufactured in Resita, in 1952, and only for such a kind of transport and shunting.

They went as follows:
- engines recorded as 1247 and 1250 to Hunedoara Steel Works;

- 1248 and 1251, to Calan „Victoria” Steel Works;
- 1249, to Otelu Rosu Steel Works;

- 1252 (number plate CFU 29) and 1253 (CFU 30) to Resita Steel Works.

Before, they manufactured a locomotive each year (1942, 1943 and 1944), type 1Dt-h2 CFU (gauge: 948 mm) for U.D.R. S.A. exclusively.

Similar from the constructive point of view, they were registered as 658, 659 and 685, number plates CFU-25, CFU-26 and CFU-17.