Transport workers shut down most rail traffic in France for a second day Thursday, frustrating passengers forced to postpone trips and Parisians who had to walk, bike or skate to work. The government awaited a response to its offer to negotiate a way out of the strikes - the first major challenge to President Nicolas Sarkozy's plan to modernize France with vast reforms. Sarkozy wants the strike to end "as quickly as possible," his spokesman said Wednesday night, and offered company by company talks in the presence of a government representative to find a solution.

Labor Minister Xavier Bertrand, in a letter to seven union chiefs, said negotiations should commence "rapidly" and be completed in a month.

However, authorities made clear that the core principle guiding a plan to reform special retirement benefits for transport and utilities workers, in place for more than 60 years, could not be touched.

"The president of the Republic has always considered that there is more to be gained for all parties in negotiation than in conflict," presidential spokesman David Martinon said. The strikes "must end as quickly as possible in the interest of passengers."

But the head of the Workers Force union, Jean-Claude Mailly, said that was not good enough. "Everything must be on the table," he said Wednesday night.

Sarkozy's call to get out of the strike quickly suggested that he did not want to risk seeing his reforms unravel. Paring down the system of special retirement benefits is emblematic of his bid to sweep away what he sees as obsolete practices.

Both the state train authority, the SNCF, which began its strike Tuesday night, and the Paris transport system said conditions had improved on the second full day of the walkout.

The SNCF said that 150 fast trains out of 700 were running Thursday, compared to 90 the day before, while the RATP which governs Paris public transport said that only one subway line was fully shut down and traffic on other lines varied from one train in five to one train in two.

Still, the streets of Paris were clogged with pedestrians and those on bicycles making their way to the office. The city's new rent-a-bike service was a popular means of locomotion.

Authorities have said the Eurostar train between Paris and London was not to be affected by the strike.

"I support the idea of strikes, but not this strike," said 25-year-old Xavier Michel, who skated 5 miles to his advertising job. This strike, he said, hurts "the little guys like us" who are "basically taken hostage."

The government as well as unions are seeking a compromise in the standoff over Sarkozy's bid to do away with an exception that allows a certain workers to retire after 37.5 years on the job, instead of the usual 40. The moneysaving device that would affect a half-million workers is meant to spur growth and put all the French on the same footing.

Utilities workers and employees of opera houses - whose curtains stayed closed Wednesday - are among those who would lose special benefits.

Sarkozy has agreed to a proposal by powerful CGT union boss Bernard Thibault for company-by-company talks with a member of the government present.

Though Prime Minister Francois Fillon said the heart of the reform was "not negotiable," Martinon, the presidential spokesman said "concrete proposals" from all sides "will naturally be examined."

This is the second transport strike in less than a month, but an Oct. 18 walkout - more crippling than the current one - was meant as no more than a warning. The current strike - with daily votes on whether to continue - is meant to wear the government down.

Written By ELAINE GANLEY