The SFMTA, which operates Muni, says it will add back 61 percent of the service cuts it made in May, but the union representing its drivers apparently has other plans.
The Transport Workers Union Local 250-A has asked a state agency that handles public employee union bargaining agreements for an injunction on the service restorations.
SFMTA spokesman Paul Rose said this afternoon that his agency was "finalizing our response to their claim."
"At this point, we're moving forward" with the restorations, Rose said.
Union officials did not immediately return calls for comment.
Among the planned changes are: extended K-Ingleside and M-Ocean View rail service past St. Francis Circle in West Portal, following the recently completed rail replacement project there; more frequent F-Market streetcar service on Market Street; and more frequent late-night Owl bus service.
Additionally, service among some of the most frequently used bus lines is being boosted, including the 9-San Bruno from Visitacion Valley to downtown, the 14-L in the Mission District, the 24-Divisadero from the Bayview to Pacific Heights, and the 33-Stanyan through the Castro, Haight and Richmond.
The May service cuts were due to budget difficulties at the time, but the SFMTA has since received a one-time allocation of funding from two local agencies, the San Francisco County Transportation Authority and the Metropolitan Transportation Commission, according to Rose.
That funding, coupled with Muni budget "efficiencies," enabled Saturday's restorations, he said.
The SFMTA is working on a plan to restore the rest of the cuts by Dec. 1.