The US-based Regional Transportation District of Denver (RTD) and its contractor Denver Transit Partners (DTP) have started testing along the G Line after securing the necessary regulatory approval.
The trials will see commuter rail trains operate along the corridor from Wheat Ridge through Arvada and into unincorporated Adams County.
G Line operations will be restricted to only a few test trains during the initial phase, which will run from Monday through Friday.
The frequency and the number of trains will be gradually increased as testing progresses toward the fully published G Line schedule.
RTD general manager and CEO Dave Genova said: “Authorisation to perform testing on the G Line is evidence of the dedication RTD and DTP have in working with the regulatory agencies to ensure a safe system for our riders.
“Safety is RTD’s top priority, and it is important for the public to be aware and exercise caution when walking, biking or driving near the commuter rail alignment.”

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By GlobalDataThe current testing programme focuses on communication and signalling systems, as well as communication between traffic and rail signals at railroad crossings.
Railroad or at-grade crossings along the alignment will be closed for the duration of the trial programme, which is set to continue for nearly 90 days.
G Line is a 11-mile electric commuter line between Union Station and Wheat Ridge in Colorado that will pass through north-west Denver, Adams County and Arvada.