COWI Holding A/S is an international engineering consulting group founded in Denmark in 1930 by Dr. Christen Ostenfeld, later joined by Wriborg W. Jønson in 1946 (operating historically as Ostenfeld & Jønson and COWIconsult). The majority of COWI is owned by the independent COWI Foundation (COWIfonden), a governance model that guarantees commercial independence, long-term reinvestment into technical innovation, and engineering research. Today, COWI employs more than 8,000 multidisciplinary engineers, geologists, environmental specialists, and digital architects across Scandinavia, the United Kingdom, North America, India, and the Middle East.

In the railway and transit sector, COWI is globally renowned for solving the world’s most demanding civil and structural engineering challenges. The firm is recognized as an international authority on long-span railway bridges, complex track-structure interaction, aerodynamic rail modeling, and subsea immersed tunnels. Landmark bridge references include acting as lead designer for the world-record Chenab Rail Bridge in India (the world’s highest railway arch bridge spanning 359 meters above the riverbed), as well as the combined road and rail Great Belt Fixed Link (Storebælt) and Øresund Fixed Link connecting Denmark and Sweden.

COWI’s railway expertise also extends across complex underground transit, high-speed rail, and urban metro systems. Key international project deliveries include major design and technical advisory roles on the Fehmarnbelt Fixed Link (the world’s longest combined road and rail immersed tunnel connecting Denmark and Germany), High Speed 2 (HS2) in the United Kingdom, the Copenhagen Metro (Cityringen and extensions), the Fornebu Line (Fornebubanen) automated metro in Oslo, Norway, and major railway electrification and capacity upgrades across the Scandinavian and North American passenger rail corridors.