An analysis of the activities of the Nevsky Plant under the leadership of S. I. Mamontov in the 1890s. The aim of the study is to determine the effectiveness of family control over an industrial business focused on the production for various transport purposes. For the first time, with the involvement of archival materials, a description of the joint work of S. I. Mamontov, his relatives and business partners on the implementation of an extensive infrastructure project is given. Particular attention is paid to the functioning effectiveness of the Nevsky Plant Partnership in its various organizational forms, production and financial situations. The ability of the key owner to coordinate his interests with the tasks of the development of a large company for any foreseeable future is considered. It is shown that the results of the Nevsky Plant activities in the 1890s were contradictory. It is followed by the ruin of its largest shareholder, on the one hand, the growth of the production potential of the St. Petersburg enterprise on the other hand. It is concluded that the bankruptcy of S. I. Mamontov not so much reflected the lack of a future for the industrial and transport companies he headed, but rather showed the discrepancy between the investment and administrative model of family business used and the scale of the technical, technological and managerial tasks facing the key owner.