(Adds background about talks, strike throughout; quote from union official)
By Laila Kearney
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 halt 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.
But due to the late hour of the settlement - announced at about 10 p.m. local time - and the logistics involved in ramping up the system from a standstill to full capacity, normal service was unlikely to be restored before the afternoon rush-hour.
Officials for the transit agency said they expected some trains to be running by 4 a.m. local time on Tuesday.
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 four-year 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."
MEDIATOR HELPS CLINCH DEAL
The breakthrough came hours after the two sides resumed bargaining Monday afternoon, conducting their talks by telephone through a federal mediator who acted as a go-between rather than meeting face-to-face, at least initially.
The latest negotiations were the first since the previous round of talks collapsed last Thursday afternoon, setting the stage for the strike.
Going into Monday's sessions, SEIU spokeswoman Cecille Isidro said the parties had essentially reached agreement on wages, pensions and healthcare contributions, while proposed work rule changes that the union criticized as potentially unsafe remained 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 tensions 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.
The unions suggested in a statement on Sunday that BART management might have been partly responsible for the deaths, saying labor officials had warned agency executives about the risks of allowing replacement drivers to operate trains.
The driver of the train in question, which was out of service and not carrying commuters at the time, has not been identified, but BART officials said the train was running on automatic control when the accident occurred.
The National Transportation Safety Board began an investigation of the incident on Sunday.
"I don't want it to be forgotten that two lives were lost during this time," Antonette Bryant, president of the Amalgamated Transit Union local, said at the late-night news conference announcing the settlement.
For months, BART management and employee unions have been at odds over pay and benefits for union workers who are demanding large pay raises, in part to offset being asked to contribute to their pensions and pay more for healthcare.
Under the terms of the last contract proposal made public, BART said it was offering a 12 percent pay raise over four years. According to management, BART workers earn $79,000 a year on average, plus benefits. The unions put the average worker's salary at $64,000.
Union representatives had said late on Sunday they had delivered a "new counterproposal" to management offering flexibility on rules governing workplace technology, but no details were disclosed.
The BART walkout is the second this year after unionized workers went on strike for 4-1/2 days in July. That strike, the first against the BART system since 1997, was called off after management and labor agreed to extend their negotiations for another 30 days.
As those talks bogged down and the unions threatened to strike again in August, Democratic Governor Jerry Brown obtained a court order imposing a 60-day cooling-off period aimed at giving the two sides more time to reach a settlement. (Additional reporting by Ronnie Cohen and Noel Randewich in San Francisco; Writing by Steve Gorman; Editing by Cynthia Johnston, Diane Craft, Lisa Shumaker and Elizabeth Piper)