 Haupt became wealthy from investments in railroads, mining, and Pennsylvania real estate, but eventually lost most of his fortune, in part due to political complications involving the completion of the Hoosac Tunnel.He and his wife purchased a small resort hotel at Mountain Lake in Giles County, Virginia.He invented a drilling machine that won the highest prize of the Royal Polytechnic Society of Great Britain and was the first to prove the practicability of transporting oil in pipes.