The third and final line of the Denver Eagle P3 commuter rail project opened on April 26, 2019 in Denver, Colorado in the USA. The G Line, which runs through residential and business areas from Denver Union Station to Wheat Ridge, has 8 local stops and also allows travelers to connect to the A Line for quick and easy access to Denver International Airport.

The first two lines, A and B lines, opened in 2016, have shown consistently good performance, with on-time trains running at 97.1% and 99.2% respectively. A total of nearly 19 million people have ridden the lines since opening, helping to reduce road congestion, improve journey times and contribute to a healthier air environment across the city. The G line was scheduled to begin operation in 2016 but was delayed because Denver Transit Partners, the consortium responsible for the implementation of the project, initially did not meet their contractual obligations. The issue concerned the approvals for the crossing gate technology. 

The estimated construction cost of the network, comprised of three separate rail lines, was US$1.2 billion at the time of the award. However, as completion has been plagued by technology issues and legal battles, costs have spiraled. 

It is estimated that the G line will carry 9,000 passengers a day and will continue with A and B line success. The line operates across communities where the train service is much-needed; it was noted that some residents and businesses have started to move into these communities in order to take advantage of the opportunities created by the new rail link.

All three lines are fitted with Positive Train Control technology – a system mandated by US Congress, which is designed to manage collision avoidance, speed restrictions and rail-worker safety. These are the first rail lines in the United States to have this technology built in rather than retrofitted.

The Denver Eagle project has been significant for the P3 model in the USA. It was the first transit P3 in the US. It has involved the construction of three new lines, with 40.2 miles of new infrastructure in total, and 18 stations. The CEO of John Laing Group, one of the companies in the Denver Transit Partners consortium has said: "The project could not have been completed on public money alone. The P3 approach is the best collaborative and sustainable way to finance and deliver complex infrastructure projects of this nature and the successful completion of the Denver Eagle project demonstrates the power of partnership between the public and private sectors. John Laing is proud to have been associated with such a success, and we hope that it will become a template for future rail and transport P3 projects in the US."