As The Atlanta Journal-Constitution reported today, there's good news about the Atlanta Beltline.

At Tuesday’s State of the Beltline Breakfast, Mayor Keisha Lance Bottoms announced that the Arthur M. Blank Family Foundation is donating $17.5 million to the development of the Westside Park at Bellwood Quarry. And a 4.5-mile segment of Southside Beltline trail is opening on a temporary basis.

But at least one vocal constituency says the state of the Beltline is unsatisfactory.

The group Beltline Rail Now is unhappy that much of the proposed light rail line along the trail won't be built for decades. And the group is threatening to try to stall further development along the Beltline unless that timetable is sped up dramatically.

“About half this room will be dead before the first (significant) Beltline rail is built,” Matthew Rao, co-chair of Beltline Rail Now, said following Tuesday’s breakfast.

In 2016, Atlanta voters approved a half-cent sales tax to pay for a MARTA expansion across the city. Last year, the MARTA Board of Directors approved a project list that includes 29 miles of light rail – including 15 of the 22 miles of proposed rail around the Beltline.

But in May the board approved a construction timetable that pushes most of that rail work beyond 2035. Transit supporters say that's not good enough.

On Tuesday, they vowed to take their grievance a step further. At the breakfast, Beltline Rail Now leaders threatened to encourage neighborhood groups to oppose waivers of parking requirements the city has been granting to encourage development along the trail. They said those waivers have been granted with the understanding that transit would soon alleviate traffic in the booming Beltline area.

“We’re getting the development,” Rao told The Atlanta Journal-Constitution. “We’re not getting the train.”

Atlanta Beltline Rail Inc. CEO Clyde Higgs noted that an extension of the Atlanta Streetcar to the Beltline on the east side of the city is slated to be finished by 2027. That includes about a mile of rail on the Beltline itself. A western Streetcar extension is set to be finished before 2035.

Transit supporters are not satisfied. Beltline Rail Now Co-Chair Patty Durand noted that a photo of a train was used as a backdrop for Tuesday’s breakfast.

“It’s ironic that they picture they have on the stage is of a train,” she said,” when there is no train.”

You can learn more about MARTA's timeline for light rail development in Atlanta here.

Read more about today's good news here.