During communism 1945-1989
The company was nationalized in 1947, and the official name changed to Fablok. Sielecki was a technical director in the post-war years until 1964. After that, he was a technical advisor to the board until his retirement on March 31, 1971. Under his leadership, the production was re-established for multiple types of locomotives, 12 of that type were destined for export.
Export markets for its standard-gauge passenger, fast, freight, and industrial steam locomotives were Albania, China, Hungary, India, Korea, Romania, and Vietnam. Narrow-gauge units were exported to Albania, Bulgaria, China, Romania, the Soviet Union, and Yugoslavia. The last steam locomotive was produced in 1963. Fablok never produced boilers for its steam locomotives, these were supplied by Fabryka Budowy Kotłów (Boiler Construction Works) of Sosnowiec known as Fitzner and Gamper before 1945; later also by other producers.
Production of diesel locomotives started in 1948. From the early 1960s, the product range diversified into rolling stock (rail and tram) components. In 1977, the production profile expanded into construction equipment and its name was changed into Fabryka Maszyn Budowlanych i Lokomotyw BUMAR-FABLOK (Factory of Building Machinery and Locomotives BUMAR-FABLOK). The factory was taken over by Zjednoczenie Przemyslu Maszyn Budowlanych BUMAR (BUMAR Association of Building Machinery Industry) in Warsaw. Production included excavators with a bucket capacity of 1.2 cubic metre, cranes with 25-28 ton lifting capacity, self-propelled road cranes, and hydraulic telescopic jibs.
