This latest contract, which has a value of about €9m (£7.25m), will see Ramboll play a central role in developing the new Haga underground station situated west of the city centre.
Ramboll's responsibilities cover construction, electrical engineering, waste water, water resources management, urban development, traffic planning and other environmental issues.
"To be selected on both the route planning and underground station elements of this important infrastructure project is a real honour and a great achievement," said Börje Eriksson, division manager for Ramboll. "This complex initiative demands a truly holistic approach and we will be drawing on multidisciplinary expertise from across the company to deliver the very best solution for the customer."
The project will be led by Ramboll in Sweden with some elements being undertaken in collaboration with colleagues based elsewhere.