The city can afford a 20-mile rail line from West Oahu to downtown Honolulu even though the project's cost has risen to $5.2 billion from $3.9 billion, officials said yesterday.

However, expanding the transit system into an envisioned 28-mile track with links to the airport, Manoa and Waikiki would require funding that has yet to be identified, city officials acknowledged.

The city plans to rely on $4 billion to be collected through a half-percentage-point excise tax surcharge and $1.2 billion it expects to get from the federal government to pay for the 20-mile rail from east Kapolei to Ala Moana, going through Salt Lake.

Mayor Mufi Hannemann's administration released a transit study in late 2006 recommending the City Council support either a 28-mile route from east Kapolei to the University of Hawaii at Manoa, or a 20-mile route from east Kapolei to Ala Moana Center, which was eventually selected.

“;This is the project we can build with what we have,”; city Transportation Director Wayne Yoshioka said. “;It's clear right now that to do both the Salt Lake and the airport together, we don't have - under the current financial scenario, under the current financial plan - we can't do that. Right now we have enough money to do the currently authorized scenario.”;

City officials declined to estimate how much the 28-mile system could cost, saying they are focusing on the shorter project chosen. They said the tax surcharge, which has raised $260 million since it kicked in January 2007, and federal funds will allow the city to build the rail without raising property taxes.

Yoshioka said that “;as we move beyond the 20-mile system,”; officials would need to devise another financial plan. He said the tax surcharge could be continued past its 2022 expiration date, the state could help pay for the airport leg and the City Council may consider lifting property taxes.

“;All of these things are on the table,”; Yoshika said. “;In due time, we'll have that discussion.”;

City Councilman Todd Apo said the Council passed a law in 2006 that prevents it from increasing property taxes to fund the rail.

“;It's an option in the future. I would call it a long shot at this point,”; he said.

The rail is expected to carry 90,000 daily riders, reduce traffic by up to 23 percent in 2030, and cost $63 million annually to operate and maintain, according to the city. An initial 4-mile segment is expected to debut in 2012 in Kapolei.

Critics have proposed alternatives, saying the rail is too expensive.

Mayoral candidate Ann Kobayashi is pushing for a $2.5 billion plan to erect an elevated highway, dedicated bus lanes and underground tunnels downtown. An anti-rail group says building two high-occupancy toll lanes along the H-1 freeway - the sole link between sprawling Kapolei and downtown - would cost $900 million and improve traffic flow by 35 percent.