The City Council was unable to reach a decision today on what technology to use in the planned $3.7 billion mass transit system.

The council voted 4-4 on a motion to reconsider the technology issue. The deadlocked vote means the council failed to select a technology. Mayor Mufi Hannemann plans to move forward with the steel wheel on steel rail option that he prefers.

The council has been debating for months whether the proposed system should use steel wheels, rubber tires or magnetically levitated vehicles. Steel is considered more reliable but noisy. Rubber and mag-lev are less tested but may be quieter.

The council was expected to cast the fourth and final vote on transit technology on Hannemann said before today's meeting that he is going with steel-wheeled trains regardless of what the council did today.

A city-appointed expert panel in February recommended the steel option as the most reliable and cost-effective.

A ninth council member, Chairwoman Barbara Marshall, was absent for the vote because of a family emergency.

The current rail effort marks the fourth time in three decades the city has tried to develop a new mass-transit system for O'ahu. Previous efforts — including two rail projects and one bus rapid-transit system — failed because of cost concerns or changes in political priorities.

Hannemann has said he wants to break ground on the new mass-transit system next year, with the first segment starting service between East Kapolei and Waipahu in 2012.