Mantena is a Norwegian rolling stock maintenance company owned by Vy (Vision). It has workshops at Grorud and in Oslo, Marienborg in Trondheim as well as in Skien, Drammen and Stavanger . In addition to NSB, customers include CargoNet, Kollektivtransportproduksjon, Ofotbanen, Green Cargo, Hector Rail and Tågkompaniet. The company was separated from NSB as a separate limited company in 2002. It has 900 employees and head offices in downtown Oslo. , that performs rebuilding of rolling stock, is a wholly owned subsidiary of Mantena.