CFU 14 belongs to a series they designed to be used on the inner industrial railroads, especially for hard transports in iron works.

Designed and manufactured for Caile Ferate Uzinale, (the Plant Industrial Railroads) and for other industrial nets, that type of Ct-n2, called Siderurgica was finally shaped in 1953 for driving and shunting hard transport within the iron plants areas.

The main benefiters of such products: Hunedoara Steel Works, with 47 locomotives; Resita Steel Works, with 36 locomotives. 24 were exported in North Korea (DPR Korea) in 1959.

The series was noted from 3105 to 3124, and 3159 to 3262 respectively, number plates from 11 to 34. The locomotive recorded as 3657 was exported in Eastern Germany (German Democatic Republic), in 1960.

Production of that type ended in 1961. Before that series, two other engines of Ct-n2 CFU (gauge: 948 mm) type were manufactured in 1943, exclusively for the industrial railways of U.D.R. S.A..

They were recorded as 674 and 675, number plates UDR 11 and UDR 12. The former locomotives of type Ct-n2 StEG 123 (gauge: 948 mm) were manufactured in 1894 (recorded as 7), and 1898 (recorded as 9).