Trainer Warren A. "Jimmy" Croll, 88, who grew up in Devon and attended the University of Pennsylvania's veterinary school before he switched career paths, died Friday night.

Mr. Croll's chosen career lasted more than a half-century and proved to be a remarkable one. Mr. Croll, who worked out of Monmouth Park, was inducted into thoroughbred racing's Hall of Fame. He won the 1987 Belmont Stakes by 14 lengths with Bet Twice - who had finished three-quarters of a length back in the Kentucky Derby and a half-length back in the Preakness.

Mr. Croll won two straight Eclipse awards for champion sprinter with Housebuster. He capped it all with the 1994 horse of the year, Holy Bull.

"One of the classiest guys I ever knew," said Bob Levy, who owned Bet Twice and Housebuster, and had horses with Mr. Croll for 30 years. "He trained horses hard. His theory was, if you're going to run in big races, you better be fit."

Holy Bull was left to Mr. Croll in the will of a client, Rachel Carpenter, who died the day the horse made his track debut in 1993 at Monmouth Park. Bred for just $2,500, Holy Bull won 13 of his 16 races and almost $2.5 million.

Levy said Mr. Croll had an eye for young talent, always going to yearling sales himself. Mr. Croll claimed a horse named Parka for $10,000 and made him the grass horse champion of 1965. His Forward Gal was the champion 2-year-old filly in 1970. He picked out Mr. Prospector in 1972, and he became one of the great sires of all time.

Croll died at Monmouth Medical Center in Oceanport, N.J. Funeral arrangements were pending.