Eric is a friend of Sheldon that appears in "The Locomotive Manipulation" (S7E15). Sheldon meets him on a train ride to Napa Valley on Valentine's Day. He loves trains as much as Sheldon. After a box landed on his head while working at UPS (six years before they meet), he went on disability and rides vintage trains. His train knowledge is quite extensive while his social skills are less than Sheldon's. Sheldon invites him to join him and Amy on their Valentine's Day dinner, much to Amy's and Bernadette's annoyance.