Neponset Greenway: A segment of the Greenway's expansion would allow users to safely navigate the gas tank property on Dorchester Bay. The proposed completion of the Neponset Greenway trail suffered another setback this week when federal transportation officials again passed over the project for grant funding.

The state was vying for a federal grant, known as TIGER IV, to provide money for completing the trail from South Boston to the Blue Hills. The proposal, now facing further delays as officials seek alternate funding sources, includes a pedestrian overpass at the Mattapan MBTA station and a bridge connecting Boston and Milton.

The state Department of Conservation and Recreation has said it would provide $2.5 million while seeking $12.4 million from federal officials. The US Department of Transportation announced the newest list of grant winners last Friday, but activists didn’t learn the news until this week.

Vivien Morris, chair of the Mattapan Food and Fitness Coalition and a top advocate for the completion of the trail, said the funds would have helped a community that feels “left out of the benefits” of the Neponset Greenway.

“I’m just devastated and very unhappy,” she said.

Morris said a walking tour of the trail took place over the weekend. “To hear a couple days later, to have our hopes of having it rectified being dashed is really disappointing,” she said.

It’s the second time the Neponset trail project has been rejected; in December, the federal department took a pass on the proposal when DCR sought grant funds known as TIGER III.

DCR Commissioner Edward Lambert said the department is disappointed, but noted that the volume and quality of applications for the TIGER grant program was high. He stressed that the department, which will be meeting with community groups and legislators who support the proposal, remains committed to completing the plan. “It’s a project that brings so many benefits to the communities and neighborhoods in terms of connections,” he told the Reporter.

Taking on the project incrementally is “one way to do it,” he said, adding that his department may submit for federal funding in a future round, but they aren’t going to wait around for approval. “We certainly don’t want to have the planning we’ve done thus far sitting on a shelf waiting for a single answer,” he said.

Morris said the state must make the project a priority. “My experience has been that when something is a priority, a real priority, you find ways to make it happen,” she said. “When things are less of a priority, they languish.”

State officials had high hopes when they submitted the application for the TIGER IV grant, saying their optimism was due to encouragement from DOT to re-apply and the anticipation of fewer proposals in this round.

But DOT received over 700 applications, and doled out funding to 47 projects in 34 states and the District of Columbia. North Carolina, Tennessee, California, and President Obama’s home state of Illinois all received funds. In the announcement laying out the grant winners, the department noted that it had received 4,050 applications asking for $105 billion during the four rounds.

Had the Neponset Greenway trail received the federal funds, construction could have started as early as August, with the Neponset Valley Parkway in Hyde Park. The one-mile segment between Milton’s Central Avenue and Mattapan Square would have started in March, and another segment, from Morrissey Boulevard to Tenean Beach, would have started in June, with the project wrapping up in fall 2014.

That timeline is now very much in doubt. “One door closed and we have to find a way to open another one,” Morris said.