Hill International has won a 30-month extension from Qatar Railways Company to oversee construction of the Doha Metro Green Line.
Hill is leading project management of the Green Line in a joint venture with ASTAD Engineering Consultancy and Project Management Company.
The joint venture will pocket $43.1m from the extended contract with Hill taking an 80% share of the total figure.
Mohammed Al Rais, regional president (Middle East) for Hill's project management group, said: "This contract extension is a reflection of Qatar Railways' confidence in the Hill team.
"We are honored that they continue to turn to Hill for our support on such an important project."
The Green Line is one of four major lines of the new Doha Metro transit system.
It runs east from Al Mansoura to Al Riffa in the west. As it passes through Education City, the line is also known as the Education Line. Aside from Education City, notable stops includes Hamad Hospital, Al Shaqab and the upcoming Qatar National Library.
The Green Line will include 11 stations over approximately 22km (14 miles) and is expected to accommodate 140,000 passenger trips per day by 2021.