A measure that ends the 23-year ban on light-rail construction in the San Fernando Valley has been signed by Gov. Jerry Brown, carving a path for optimizing the use of the Orange Line.

Assembly Bill 577, by Assemblyman Adrin Nazarian, D-Sherman Oaks, would allow the building of above-ground rail, but any such project could run into a roadblock with the Metropolitan Transportation Authority over its potential cost.

“It would be premature to speculate on routes, costs or a timeline,” Metro spokesman Marc Littman said. “The Metro board could ask for an analysis of what it would cost to convert the Orange Line busway to light rail.

“But no funding for a project has been identified since it was not permitted under law to consider light rail before this measure became law.”

Nazarian said his plan will provide the flexibility to address the growing demands for public transportation in the greater San Fernando Valley.

“This is a first step that we had to take to eliminate the restrictions on construction,” he said. “Now we can begin studying what we can do and how to pay for it.

“By repealing the ban of light-rail installation along the Orange Line, (the measure) allows the Valley to take the first step toward a 21st-century transit system, which will lead to greater connectivity to the Red Line and other transportation lines throughout Los Angeles and the San Fernando Valley.”

In 1991, then-state Sen. Alan Robbins, D-Van Nuys, in a dispute with local transit officials, was able to enact the ban on any transit construction unless it was a subway.

Mayor Eric Garcetti, who took over as MTA board chairman on July 1, supports the idea of Nazarian’s bill, spokeswoman Vicki Curry said.

“Mayor Garcetti is committed to increasing transit options to keep traffic moving,” she said. “Converting the Orange Line to light rail will increase capacity, and as chair of the MTA, the mayor will support a study of this option.”

Valley Industry and Commerce Association had initially approached Nazarian about introducing the measure, noted the group’s president, Stuart Waldman.

“The Orange Line was designed to be converted to light rail,” he said. “It runs parallel to the 101 Freeway and is our best option to get people out of their cars. And the Orange Line is close to capacity.”

According to MTA officials, the Orange Line has 30,000 weekday boardings. Waldman said the next step is to ask the MTA board to approve a study that explores ways a project can be undertaken.

Funding will be the major issue, with estimates of $100 million a mile. Nazarian said it would be up to local officials to appeal to the federal government for help in financing any new system.

A Valley light-rail line would not be eligible for funds under the Measure R sales tax because it was not included in the list of projects to be funded. Waldman said he expects another sales-tax proposal to be considered in the near future that could go for other transit projects.

The 18-mile Orange Line, which runs from Chatsworth to North Hollywood, has proven one of Metro’s more popular routes. And while there would be a reluctance by transit officials to have a break in the service, Waldman said the work could be phased in with only minimal disruption.