A judge's decision on Tuesday gave RTD the green light to resume testing on the Gold Line.
That line would run from Union Station in Denver through Adams County, Arvada and onto Wheat Ridge.
The Gold Line -- or the G Line as it's also called -- has not tested trains since July.
Both the G Line and the A Line use commuter rail trains.
RTD has been trying to resolve issues with crossing warning times on the A-Line, and the 15 crossings on the G-Line use the same technology.
Tuesday's decision means once testing starts up again on the G Line, there will be flaggers at all crossing and that train horns will sound as trains approach crossings.
