John Paul Alpert, 19, of Palmdale, Los Angeles County, described by police as a normally responsible young man who has never been in trouble with the law, was found dead on May 15 by an angler fishing in Dry Creek.
His remains were close to the creek bed near Atkinson Street, which is not far from the Roseville railyard.
Roseville detectives, working with the Placer County Coroner's Division, identified the remains as those of Alpert. Police said that before he began his freight train adventure, he lived at home with is parents and attended community college.
He left Palmdale in March, traveling north with a group of freight rain riders. Alpert had never hopped a freight train before, which is an illegal practice.
Soon after he left Palmdale, he stopped communicating with his family. His family reported him missing on March 25.
Detectives believe that Alpert arrived in Roseville aboard a freight on March 16 or March 17 and was killed. His body had blunt force injury.
Detectives asks that anyone who saw Alpert in mid-March in Roseville, have knowledge of his killing or had contact with freight train riders about that time to call the department's investigations unit at (916) 774-5070.