There's still no timeline for the RTD G Line between Denver's Union Station and Wheat Ridge to open, but officials received key federal approvals Wednesday.
From why the feds are issuing threats now to the difference between commuter rail and light rail.
At issue are crossing gates that, in some instances, come down too early and stay down too long.
In its filing, Denver Transit Partners also urged the court to reject RTD’s counterclaims.
The filing paints a chaotic portrait of the months and years leading up to the A Line opening in April 2016.
The Denver Post reports a "safety critical software problem" at some crossings prompted the return of the guards.
Internal disciplinary records obtained by CPR News show engineers have made dozens of serious mistakes in the last two years.
The hold-up is over the wireless system that controls the A, B and G lines’ crossing gates.
The PUC Chairman took issue with an RTD spokesman's comment about the regulatory process.