SAN FRANCISCO (CBS SF) — Leaders of San Francisco Municipal Railway’s transit operators’ union on Tuesday defended what they maintain is their right to strike if labor negotiations break down with the agency.

Transport Workers Union Local 250-A, which represents the roughly 2,200 operators of Muni’s buses and light-rail vehicles, began a weeklong voting process last Friday that would authorize its leaders to call a strike, even though the union’s current contract has a no-strike clause.

READ MORE: 3-Alarm Fire Burning at West Oakland Recycling Center

Union Secretary-Treasurer Walter Scott maintained that the strike prohibition clause was “open for legal interpretation” and has “never been tested.”

“Like good Boy Scouts, it’s always good to be prepared” in case talks break down between the union and the railway’s governing agency, the San Francisco Municipal Transportation Agency, Scott said.

He indicated that the vote, which runs through Thursday and requires majority approval, came after a general membership meeting last month in which concerns were raised about clauses in the city charter that he said have not been honored by the SFMTA.

“There are some things that concerned the members, and we do have to respond to the members’ wishes,” Scott said.

The vote comes during the second month of negotiations between the two sides, and comes just as the two sides were getting to the point of exchanging proposals, SFMTA spokesman Charlie Goodyear said.

“That’s what makes this vote all the more puzzling,” Goodyear said.

He said the agency “encourages unions to keep working with us at the bargaining table. That’s where the work and the focus needs to be.”

Goodyear said the two sides had a relatively short amount of time to reach a compromise before the end of the current fiscal year in June, when an agreement between the two sides has to be presented to and approved by the SFMTA board of directors.

READ MORE: 2 Windsor Teens Shot Friday Evening, Suspect in Custody

The agency, which faces a projected budget deficit of about $18 million, is proposing to save money by eliminating inefficient work rules and making changes to the salaries and benefits of its employees, Goodyear said.

He said the average transit operator currently makes about $101,000 per year in salary and benefits.

Scott said the union was open to making concessions, including contributing to their retirement benefits and agreeing to a wage freeze.

He said the authorization vote does not mean “that this (union) wants to go on strike. We’ve had a good relationship in negotiations, and I’m pretty sure we’re going to come to a pretty good medium on this.”

The negotiations between the two sides are the first since San Francisco voters approved Proposition G last November.

The proposition, spearheaded by Supervisor Sean Elsbernd, changed parts of the city charter that required Muni drivers to be paid the second-highest operator salaries in the country, and it now requires contracts be negotiated through collective bargaining and binding arbitration, similar to other city employees.

Supervisor Scott Wiener condemned the union’s strike authorization vote at Tuesday’s San Francisco Board of Supervisors meeting, calling it “incredibly tone deaf.”

Wiener said the passage of Proposition G provides “a unique opportunity to reform Muni” and “an opportunity in a horrific budget year to help the MTA save some money.”

He said he hoped the union members vote down the authorization of a strike, which he said would be “a terrible move.”

MORE NEWS: 12-Year-Old Arrested For Setting Fires In Tinder-Dry Berkeley Hills

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Wire services may have contributed to this report.)