Jane Welzel, a 25-year-old assistant track coach at Penn State, won the Bonne Bell 10-kilometer (6.2 miles) road race yesterday in the rain at West Potomac Park with a time of 35 minutes, 38 seconds, beating out Marge Rosasco and a field of 3,000.

Welzel, Rosasco and eight other runners broke away from the pack within the first half mile and the two, who decided to run as a pair prior to the race, maintained their lead throughout. Welzel pulled ahead of Rosasco at the 4 1/2 mile mark and never gave up her lead. Rosasco, of Fallston, Md., finished with a time of 36:41.

Welzel and her 20-year-old sister, Linda, who finished fourth in 37.40c are from Hopkinton, Mass. "Our claim to fame is that's where the Boston Marathon begins," Jane said.

Marie Earl, the top Washington area finisher and a member of the Washington Runhers, took first in the 20-29 age group with a time of 38.03 and sixth overall. The 23-year-old legislative aide for the Senate Subcommittee on Investigations moved to the District last June and runs daily, averaging about 80 miles a week.

"I started running in law school (at Boston University)," she explained.

Aside from running, which she's done for about a year and a half, she plays racquetball, tennis and basketball and plays soccer with the Eastern Express. r

Carolyn Fellowes, a sophomore from the University of North Carolina-Chapel Hill, finished first in the 13-19 age group. A member of the Tidewater (Va.) Striders, the race's team winner, Fellowes has been running for four years.

With 3,500 registrants, the Bonne Bell claims to be the third biggest women's race in the country.

Only about 500 women were deterred by the early morning rain and chilly breezes blowing in from the Potomac and Tidal Basin.