DETROIT (AP) - Regional transportation planners have ruled out light rail and other options for a mass transit connection between Detroit and Ann Arbor, but still believe there is potential for a streamlined commuter rail.

The Southeast Michigan Council of Governments released a study on five transit alternatives for the 50-mile corridor. None of the options _ which included locomotive-powered commuter rail, light rail and bus routes on high-occupancy-vehicle lanes - proved feasible, said Alex Bourgeau, SEMCOG's coordinator of intermodal transportation.

"The numbers that we got as far as ridership and costs on the five alternatives are not competitive nationally," he said yesterday. "We have to compete for that (federal) money against the New Yorks and Chicagos."

However, that doesn't mean the region should give up on the idea, Bourgeau said. He said of the five alternatives, SEMCOG picked a commuter rail option that uses an existing track owned by Norfolk Southern Corp. Planners will now focus on a streamlined model of that option that involves less frequent service and avoids some additional capital investment that was part of the original model.

In addition to using the track owned by Norfolk Southern, the option would rely on existing Amtrak stations.

"Right now we have to really roll up our sleeves and start talking to the people who own the stuff," Bourgeau said.

Bourgeau said a revised model should be ready by January and regional officials could conceivably have a proposal ready to submit to the federal government by March.

He said a cheaper option would be more competitive for funding, or the region's governments could choose to put something in the ground on their own and hope federal money would come later for expansion.