Kolowag
Kolowag is a Bulgarian manufacturer of railway wheelsets and freight wagons, operating from Septemvri under the legal entity Kolowag AD (until 2017 Vagonoremonten Zavod-99 AD, VRZ-99) and supplying wagon keepers and wagon builders across Europe.
The plant was founded in 1941 as a railway carriage repair workshop serving the narrow-gauge line between Septemvri and Dobrinishte. On 24 June 1999 it was privatised out of Bulgarian State Railways (BDŽ) as VRZ-99 AD, and the entity was renamed Kolowag AD in January 2017. Wheelset production began in 1983 and shifted the plant’s centre of gravity from carriage repair towards rolling stock components.
The company is family-controlled: three generations of the Yonchev family sit on the five-member board, and Emil Stoyanov Yonchev is chief executive and the company’s registered representative. Bulgarian press reporting put revenue for 2022 at BGN 252 million, about EUR 129 million, with a workforce of around 1,460 and 49,000 m² of production halls.
Products
Production splits between components and complete vehicles. The wheelsets and wheel discs range covers new wheelsets for freight wagons at axle loads of 20 t, 23.5 t and 25 t, with wheels and axles also supplied separately. Variants include wheelsets with brake discs, thick protective coatings, small-diameter wheels down to 730 mm, and driving wheelsets for powered vehicles.
Repairs and reconditioning span the VPI (Verband der Güterwagenhalter in Deutschland) maintenance levels IL, IS 1, IS 2 and IS 3, following the plant’s first VPI audit for wheelset repair in March 2010. The company puts annual wheelset production at 25,000 to 30,000 units since 2008.
A second production line builds complete freight wagons — double pocket, container, tank, box and platform types — together with Y25-family bogies, drawing on 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.
The plant obtained a product qualification certificate from DB in June 2012 for wheelset production to DIN EN 13260 and BN 918274, and was certified as an entity in charge of maintenance (ECM) in July 2013. Wheels and axles passed TSI conformity testing at the VUZ railway research institute in Prague in 2010, covering wheelsets up to 25 t axle load.
Current activity
LTG Cargo Polska took delivery of 72 pocket wagons built by Kolowag during 2025, financed through Poland’s national intermodal transport recovery fund. The wagons entered service on the Kaunas–Duisburg intermodal corridor in April 2026, replacing leased stock. In September 2025 Kolowag delivered a batch of Zacns 98 m³ tank wagons to the leasing company ERR European Rail Rent.
Two EU co-funded projects run into 2026: a workplace-adaptation scheme with a budget of EUR 240,000, ending in July 2026, and a product development project with the Bulgarian partner TOSS AD, budgeted at EUR 639,000 and running to September 2026. An earlier project under Bulgaria’s national recovery and resilience plan, started in November 2023 with an 18-month term, installed photovoltaic capacity with battery storage for own consumption.
