(Updates with strike settlement reached)
SAN FRANCISCO, Oct 21 (Reuters) - Striking San Francisco-area transit workers reached a tentative contract deal with management late on Monday to end a four-day walkout that has paralyzed the nation's fifth-largest commuter rail system, union and transit agency officials said.
Union representatives said they were calling an immediate end to the strike by the 2,000-plus Bay Area Rapid Transit (BART) employees who walked off the job last Friday in a dispute over wages and workplace rules.
Officials for the transit agency said they expected some commuter trains would be running by 4 a.m. local time on Tuesday, and that full service would hopefully be restored by the afternoon.
BART General Manager Grace Crunican said details of the settlement would not be made public until union leaders have a chance to discuss the terms with their members.
The tentative accord must be voted on and ratified by union rank-and-file, and be approved by BART's board of directors before it takes effect.
The two unions involved - Service Employees International Union (SEIU) Local 1021 and Amalgamated Transit Union (ATU) Local 1555 - said the deal "provides for reasonable wage increases, a compromise on pension and healthcare costs (and) work rule changes that allow for innovation and input from workers."
Crunican described the package as providing "more than we wanted to pay, but it is also a new path in terms of our partnership with our workers and helps us deliver the BART service for the future."
The breakthrough came hours after the two sides resumed bargaining Monday afternoon, with the parties conducting talks by telephone with a federal mediator acting as go-between instead of face-to-face, at least initially.
SEIU spokeswoman Cecille Isidro said on Monday the two sides had essentially reached agreement on wages, pensions and healthcare contributions, while work rules that the union says could lead to unsafe conditions were the chief stumbling block.
BART officials said the two sides were still in dispute over economic issues at the time talks resumed.
The strike has idled a commuter rail system that serves more than 400,000 round-trip riders a day in San Francisco, Oakland, Berkeley and outlying suburbs, causing severe rush-hour gridlock in one of the most traffic-clogged cities in the United States.
BART ranks as the fifth-largest U.S. rapid transit system by ridership, after New York City, Washington, D.C., Chicago and Boston, according to data from the American Public Transportation Association.
The strike, a continuation of labor strife that led to an earlier walkout in July, took a tragic turn on Saturday when two transit workers - a BART manager and a contractor - were struck and killed by a BART train while inspecting a section of track.
(Additional reporting by Ronnie Cohen and Noel Randewich in San Francisco; Writing by Steve Gorman; Editing by Cynthia Johnston, Diane Craft and Lisa Shumaker)