The G Line, also known as the Gold Line during construction, is a Regional Transportation District (RTD) electric commuter rail line between Denver Union Station and Wheat Ridge, Colorado. Long scheduled to open in October 2016, the opening was delayed until mid-2019. The reason specified for the delay was timing issues experienced by the other commuter rail lines in the RTD system, which currently require a Federal Railroad Administration waiver to operate their grade crossings manually, and the wireless crossing system used by those lines.