The US-based firm has an 80 percent stake in a joint venture with Astad Engineering, and has been working on phase one of the line’s construction since 2012.
The JV will continue managing the project for at least another 30 months, it said.
This takes it into late 2019, when the first phase of the Doha Metro is scheduled to open to passenger traffic.
The Green Line is one of three lines expected to launch at this time.
It will run from Al Rayyan Stadium to Msheireb via Education City. The line’s 11 stations include stops at Hamad Hospital and the upcoming Qatar National Library.
Also in 2016, Hill was awarded a multimillion-dollar contract to manage Qatar’s delayed Lusail light-rail project for the next four years.
The news comes amid a difficult period for Hill, which saw second-quarter net profits drop 66 percent to $1.5 million.
According to the National, this was largely due to a decline in fees from Hill’s Middle East project management arm.
However, chief executive David Richter said in a conference call this week that the firm expects business to pick up in the region soon.
“(It) will flatten and begin to get back to some level of growth,” the National quotes him as saying. “My guess is by the fourth quarter, we will have stabilized and we will be looking at growth in 2017 again.”