20th century
In the early 20th century, the bridge construction activities expanded even further. In 1902 K. Rudzki i S-ka entered into a cartel agreement with several similar Russian firms and secured 17 percent of all bridge construction contracts in Russian Empire. Altogether in the first two decades of the 20th century the company built 5,000 metres of steel road bridges and 24,000 metres of various rail bridges for 37 different railway companies, in addition to providing them with a net of over 2 million metres of water pipelines. Among the steel bridges constructed by K. Rudzki were Warsaw's Poniatowski Bridge, but also most of Trans-Siberian Railway's river crossings, including the 1916 Khabarovsk Bridge (at over 2,500 metres of length for decades the longest bridge in Eurasia). The company also built bridges for the Orenburg-Tashkent Railway, Saint Petersburg–Warsaw Railway, Amur Railway (all bridges on the eastern and middle sections of the line), Ussuri Railway and Chinese Eastern Railway, among others. The company was also one of principal contractors during the construction of St. Peter and St. Paul's Church in Warsaw (now St. Barbara's Church in Warsaw) (1894) and Hale Mirowskie (1899–1901), it also continued to produce machinery for railway companies, overhead cranes, elevators, artillery, boilers, centrifugal pumps, water turbines and many other types of machinery. It was also one of principal military contractors, producing artillery shells (since 1905), shrapnel ammunition (since 1909) and airship hangars (1914). Between 1893 and 1914 the equity of the company rose by a factor of 6, from 600,000 roubles to over 4 million. Total sale value for 1914 amounted to 11.6 million rubles.
The growth of the company stopped due to the outbreak of World War I. After the war, the Russian Revolution and the Polish-Bolshevist War, the company was permanently cut off from its eastern markets and production branches of the firm never recovered. It continued as a construction and engineering company. Despite attempts at entering the automobile production market through Ralf-Stetysz cars, in 1933 the Warsaw factory was closed down completely and only the Mińsk Mazowiecki plant remained operational. The equity of the post-war company remained high nevertheless, with over 4.32 million Polish złoty in 1924. The company continued to participate in some of the most difficult engineering projects of the interbellum, including the construction of Maurzyce Bridge, the first welded road bridge in the world, in 1927. It also built the Transatlantic Radio Exchange in Stare Babice, one of the largest radio stations of the epoch. However, due in part to the Great Depression, the value of sales continued to drop, from 17.5 million złotys in revenue in 1929 to 5.7 million in 1936. The company, however, was still one of the principal bridge constructors in Poland, securing many prestigious contracts, such as the Ignacy Mościcki Bridge in Puławy.
One of the last bridges completed by K. Rudzki i S-ka before the war was the Legions of Marshal Józef Piłsudski Bridge across Vistula in Płock. The difficult construction of the then-longest bridge in Poland was completed in under two years by K. Rudzki i S-ka and another company, Przedsiębiorstwo Robót Inżynieryjnych Leszek Muszyński. The bridge was opened for traffic in late 1938 and demolished only a year later, during the opening stages of the Invasion of Poland.
During World War II, the factory was nationalised by Nazi Germans and given to the Krupp concern and renamed to Krupp Bridge Factory. Initially it housed a German POW camp for Polish, French and Soviet prisoners of war. With time the POW camp was moved to another place nearby, while the factory started to increasingly rely on slave labour, notably from the Mińsk Mazowiecki Ghetto. After the liquidation of the ghetto in 1942, several hundred Jewish workers remained in the former Rudzki plant, but the last 104 of them were mass murdered by the Germans on 5 June 1943.
After World War II, the factory was nationalised and officially ceased to exist in 1948. Its production plant in Mińsk Mazowiecki was not damaged by the war, but was nationalised and then taken over by a new, state-owned company producing steel elements for bridge construction, overhead cranes and similar machinery. Its descendant now functions under the name of Fabryka Urządzeń Dźwigowych.