Testing for the long-awaited Regional Transportation District G Line commuter rail is scheduled to resume Tuesday after a judge gave his approval this week.

The rail, which still doesn’t have an opening date, will connect Union Station and Wheat Ridge, passing through Arvada on the way. Most of the testing will take place Monday through Friday from 8 a.m. to 6 p.m. during the first two weeks of January with one train, according to RTD.

The testing will focus on communication and signaling systems. People along the rail should expect train horns during testing as quiet zones haven’t been established.

The train was initially supposed to open in October 2016. The project has been delayed several times due to timing issues at crossing gates along both the University of Colorado A-Line to the airport and the B-line to Westminster.

All three lines use the same crossing technology. The already running A-Line and B-Lines are allowed to operate under the condition that each crossing is staffed by flaggers around the clock.

In September, the Federal Railroad Administration approved RTD’s design for the gates, but the PUC ruled the opposite way, citing concerns over potentially dangerous driver behavior caused by excessive wait times at the crossings.

A three-day hearing to consider the safety of the crossings is scheduled to start March 12, although it could be pushed up to Feb. 15 if no objects are raised by freight rail lines that use the same corridor or several cities along the tracks.