Development of railway traffic in Slovakia, in the first half of the 19th century, created a higher demand for maintenance of railcars. A workshop in Trnava was built from 1922-1924 for these purposes.

The history of this repair shop starts in 1925, when the first revision of a freight railcar was made. In the following years, there was a search for an optimal system of organizing repairs. The high demand for repairs of damaged railcars after World War II, brought a change from the original box system of repairs to the line system. In this way, it was possible to repair 3,500 freight cars a year. Besides freight cars, motor cars and passenger cars were repaired. Up to 1951, road vehicles were repaired. After 1980, cranes were also repaired here.
Major investments in building new and reconstructing old premises, which started in 1968, continue to be the investment base of the company. Since the end of the 60's, more than 10,000 cars have been annually repaired here.

Since 1994, the workshop is a joint stock company, ŽOS Trnava, a. s., The major shareholder is TOS spol. s r.o. (50.8% of shares). The other shareholders are ŽSR (34% of shares) and Železničná preprava spol. s r.o. (15.2% of shares).

The new company continues in the tradition of the old and focuses especially on repairs of all kinds of freight railcars. At the same time, the company has expanded its activities by modernization and reconstruction of freight railcars; repairs, modernization and reconstruction of passenger cars; production of new railcars; and by machinery production for foreign partners.