Železničné opravovne a strojárne Zvolen a.s., (ŽOS Zvolen) is the biggest and most significant company focusing on reparation and modernization of motor locomotives and motor railcars in Slovakia. The reparation of railway vehicles has got tradition for 140 years, since the creation of railway manufactory in 1872. From the historical view, the one of the most important year is "1994", when the company formed into joint-stock company, and it separated from The Railway Company of Slovak republic. Repair manufactory of Zvolen become major owner of the company and after that, in 2008 The company have become part of ŽOS Trnava Group