The body was discovered at about 7:20 a.m. at the foot of an embankment south of Valley Avenue and east of Case Avenue, police said. The death is being considered suspicious.
The victim was a white man who appears to have been in his late 40s or early 50s, with thinning gray hair, who was mostly bald, police said.
He was between 6 feet and 6 feet 2 inches tall, and he weighed 250 to 260 pounds. He was wearing gray shorts and a blue long-sleeved sweatshirt, and had tennis shoes at the time of his death.
He did not have any identification on him and had not been identified as of this evening.
The man appears to have been walking down the railway easement and might have been heading home from Raley's Supermarket, police said. He might have been homeless and had an encampment somewhere nearby.
Anyone with information about the man's identity or death is asked to call police at (925) 931-5100.