Kolowag
Kolowag is a Bulgarian manufacturer of railway wheelsets and freight wagons, operating from Septemvri under the legal entity Kolowag AD (until 2017 VRZ-99 AD) and supplying wagon keepers and wagon builders across Europe.
The plant was founded in 1941 as a railway carriage repair workshop and built Bulgaria’s first wheelset workshop in 1983. In 1999 it was privatised out of Bulgarian State Railways (BDŽ) as VRZ-99 AD.
The company is family-owned, with three generations of the Yonchev family active in management under CEO Emil Yonchev. According to Kolowag, it employs around 1,400 people with an annual turnover of EUR 120 million and 49,000 m² of production halls.
Products
Kolowag produces new wheelsets for freight wagons at 20 t to 25 t axle loads, along with wheels and axles as separate components. The range includes wheelsets with brake discs, protective coatings, and small wheel diameters for low-floor applications.
Repairs and reconditioning cover the VPI (Verband der Güterwagenhalter in Deutschland) maintenance levels IL, IS 1, IS 2 and IS 3. The company states an annual output of 25,000 to 30,000 wheelsets since 2008.
A second production line covers complete freight wagons — double pocket, container, tank, box and platform types — as well as bogies, supported by an in-house design department.
Market position
Kolowag describes itself as the only producer and repairer of wheelsets in Bulgaria. Its customers are wagon keepers and wagon manufacturers across Europe, with deliveries concentrated in the standard-gauge freight market.
Kolowag holds a product qualification certificate from Deutsche Bahn for wheelset production to DIN EN 13260, issued in 2012, and reports certification as entity in charge of maintenance (ECM) since 2013. Its wheelsets for standard European axle loads are TSI-approved, according to the company.
Current activity
In September 2025, Kolowag delivered a batch of Zacns 98 m³ tank wagons to the leasing company ERR European Rail Rent.
Several EU co-funded investment projects run through 2026, including photovoltaic systems with battery storage for own consumption and, according to the company’s own announcements, a circular-economy transition programme under Bulgaria’s recovery and resilience plan.
