His principal staff duties included Director of the Joint Staff, Office of the Joint Chiefs of Staff; Executive Assistant to the Chairman, Joint Chiefs of Staff; and Executive Assistant to the Chief of Naval Operations. He served as an aide to the Chairman of the Joint Chiefs of Staff Admiral Thomas H. Moorer.
After retiring from full-time military service, Train composed his memoirs, Reminiscences of Rear Admiral Harry D. Train II, U.S. Navy, which he published through the Naval Institute Press in 1997. Train also worked for Science Applications International Corporation (SAIC), the nation's largest employee owned research and engineering company. He retired from SAIC as its Manager, Hampton Roads Operations, in September 2006.[2]
Train served as a commissioner on the U.S. Commission on National Security/21st Century.[6] He is a member of the Board of Trustees of the Old Dominion University Research Foundation,[2] and was the long-time president of the Future of Hampton Roads, a group of civic leaders who work toward regional solutions in Hampton Roads, Virginia.[7]