Oahu planners will soon be getting outside help to spur more affordable housing and create more walkable neighborhoods near the island’s future rail stations.

The Federal Transit Administration announced Monday it selected Honolulu and eight other cities to join its “National Public Transportation/Transit-Oriented Development Technical Assistance Initiative.” Transit-oriented development, or TOD, refers to residential and mixed-use projects designed to fit well with nearby public transit systems, such as rail.

The federal program will provide those cities with help from Smart Growth America, a nationally renowned advocacy group that promotes such development.

“It’s significant. It was a competitive national application. It’s a nod from FTA both that we’re doing something right but that we need help,” said Harrison Rue, the city’s Community Building and TOD administrator. “It’s just another check to help us make sure that what we’re doing is on the right track, and a little bit of counsel … on what we should be focusing on first.”

The city is building a 20-mile, 21-station rail project that planners hope will encourage developers to build transit-oriented projects along the route.

It’s not clear yet exactly what the technical assistance to Honolulu will entail, but it will likely involve workshops and visits by Smart Growth officials to examine local zoning, land-use rules and discuss the best strategies and incentives to bring about TOD, Rue said.

“Due to (Honolulu’s) high land and construction costs and lack of resources, affordable rental housing is exceptionally hard to develop,” a one-page FTA document describing the city’s challenges stated. The city has found that the area around the rail line will need some 25,000 more affordable housing units, it further stated.

The program will likely include at least one workshop that’s open to the public, he added.

The entire national FTA initiative is slated to last four years, but Rue said Honolulu would participate only for part of that period — exactly how long depends on the plan created in coming weeks.