Honolulu is on track to pick the oldest, noisiest technology for a planned $3.7 billion commuter rail line connecting East Kapolei to Ala Moana Center.

Steel wheels on steel rails represents the most reliable and cost-effective means of moving masses of people in and out of urban Honolulu, but it is also the loudest, according to a city-appointed panel of experts.

Steel-on-steel technology could be a problem for some residents near the elevated tracks, where trains will pass at up to 55 mph about 400 times a day from 4 a.m. to midnight.

The biggest noise impact would be along Salt Lake Boulevard, though neighbors along Farrington and Kamehameha highways and Dillingham Boulevard also could be affected, according to a city consultant.

Much of the area near the tracks is relatively noisy, which should mitigate train noise, said Mayor Mufi Hannemann. In addition, new technologies make steel-wheeled trains quieter than in the past.

"The feeling is that by the time we start building, there will be an improved technology to mitigate that, but there's no question (noise issues) are going to exist," Hannemann said. "It comes down to choices. Do you want to go forward with this or do you want to just deal with the impacts of what we've been experiencing so far."

The increased noise pollution could also hurt the value of properties near the commuter rail line, but that could be offset by the added value of easy access to mass transit.

"There's both positive and negative (effects) ranging from noise intrusion into existing residential areas to convenience and retail opportunities at transit stops," said James Hallstrom, president of Honolulu appraisal firm The Hallstrom Group Inc.

Hannemann hopes to break ground on the project next year, with the first segment starting service between East Kapolei and Leeward Community College in 2012. The city's plan calls for adding service to Ala Moana Center by 2017.

TRAFFIC ALTERNATIVE

The transit system is expected to give commuters an alternative to increasingly congested highways and reduce urban sprawl. The project won't prevent traffic along the busy H-1 commuter corridor from worsening.

An expert panel decided last month to recommend steel wheels on steel track instead of quieter technologies such as monorail and magnetic levitation. They concluded steel was the best option based on reliability, safety, ride quality and cost.

How noise from the trains will affect neighbors along their 20-mile route will depend on a variety of factors, including existing noise levels, proximity of homes to the track and the type of train used.

The train is expected to generate no more than 75 decibels of noise at a distance of 50 feet, according to the city. In Salt Lake, the elevated train's route is expected to pass no closer than 100 feet from homes, though the distance could be closer in other communities. The city did not specify what the noise level will be at 100 feet.

Generally, 75 decibels equates to the noise made by a vacuum cleaner at 5 feet, or a jet flying 5,000 feet overhead, said Todd Beiler, an acoustical consultant at D.L. Adams Associates Inc. in Kailua. Under Federal Highway Administration rules, traffic noise next to homes should not exceed 67 decibels, he said. A city bus when accelerating generates 83 decibels within 50 feet, the city says.

Existing noise levels, primarily from street traffic, along Salt Lake Boulevard range from 59 to 69 decibels, according to New York-based project consultant Parsons Brinckerhoff.

That relatively high level of existing noise could mask train noise, Beiler said.

"If the existing ambient noise level is already at that noise level or maybe slightly above that when the rail goes by, you're not really going to hear it so much because the ambient noise masks the rail noise," he said. "If the train is going to emit the same noise through a quiet neighborhood, then there will be a bigger impact."

The steel-rail train would cause "severe" noise at 55 locations, all in Salt Lake, and "moderate" noise at 397 other locations in Salt Lake and along Farrington and Kamehameha highways, according to a May 2007 report prepared by Parsons Brinckerhoff.

ANNOYANCE FACTOR

The introduction of new noise into a community is considered severe if a significant percentage of people would be highly annoyed, according to the Federal Transit Administration, which oversees such projects. A moderate noise impact would be noticeable to most people, but may not cause strong, adverse community reaction, according to the agency.

Monorail technology would generate no "severe" noise along the proposed route and "moderate" noise at 282 locations, primarily in Salt Lake, according to the Parsons Brinckerhoff report. Magnetically levitated vehicles, which float above their track, would have no noise impact, the report said. The report did not cover the potential noise impact of rubber-tired bus technology.

The city-appointed panel that recommended steel was made up of five transit system experts who spent a week weighing proposals from 10 different vendors representing steel on steel, rubber tires on concrete, magnetic levitation and monorail technology. Four of the panelists rated steel technology the noisiest, though still within acceptable levels. One panel member rated rubber tire technology the noisiest.

Both magnetic levitation and monorail technologies were ruled out because of cost, capacity and technology concerns.

Apart from the type of technology used, other ways to ease train noise include: lubricating rails, using vibration absorbers and properly maintaining tracks and wheels to reduce squealing, according to the Federal Transit Administration.

Noise impacts could also be limited by building a 3- to 5-foot wall along the sides of the nearly 30-foot-high track, according to Parsons Brinckerhoff.

The city-appointed panelists said their recommendation was based on limited information about the costs of the different technologies. They went with steel in part because there are at least five potential vehicle vendors for steel, which are more vendors than any of the other alternatives, and will make the bidding more competitive.

The city's Committee on Transportation and Public Works voted 4-1 on Feb. 28 to accept the recommendation of the expert panel in favor of steel wheels.

The City Council is expected to vote on the issue three more times before its decision is final.

The lack of detailed cost information raised concern among some council members.

"By their own admission (panelists) did not get any information on costs from most of the respondents to the (request for information)," said council Chairwoman Barbara Marshall, during a recent hearing. "I think that's critical.

"The whole idea here was that we were supposed to select a system based on cost efficiency."

Council member Romy Cachola, who represents the Salt Lake/airport area, agreed the council needs more information about costs and noise of various technologies.

"Listening to the people in my district, that's what they want to know," he said. "How much does this technology cost compared to the others? I cannot answer because there's no detail as to that."

AIRPORT ROUTE

Another alternative to ease the noise impact would be to skip Salt Lake in favor of a route that runs by Honolulu International Airport along the H-1 viaduct. That route would generate no noise impact, according to Parsons Brinckerhoff. Hannemann prefers the airport route.

The Salt Lake route was selected over the airport route because Cachola threatened to vote against the project unless it was routed through Salt Lake.

Hannemann said, "I used to live in Salt Lake (so) I know how narrow that boulevard is. I think once (Salt Lake residents) see it, touch it, (and) see it coming, they may give Romy some push back."

Reach Sean Hao at shao@honoluluadvertiser.com.