Diaries, correspondence, speeches and writings, governmental and organizational records, topical files, photographs, and other papers relating chiefly to Train's work as a conservationist and environmentalist in public and private sectors on national and international environmental issues and policies. Documents his service with the African Wildlife Leadership Foundation (later the African Wildlife Foundation), Conservation Foundation, Council on Environmental Quality, North Atlantic Treaty Organization's Committee on the Challenges of Modern Society, U.S. Dept. of the Interior, U.S. Environmental Protection Agency during the Richard M. Nixon and Gerald R. Ford administrations, and World Wildlife Fund. Individuals represented include I︠U︡.A. Izraėlʹ, and Fairfield Osborn. Subjects include environmental diplomacy with China, Germany, and Spain, with Canada leading to the Great Lakes Water Quality Agreement of 1972, and with the Soviet Union establishing the Joint US-USSR Committee on Cooperation in the Field of Environmental Protection. Includes travel journals kept by Train while on safari and other private and official travel.

Correspondents include Tom Bradley, George Bush, Earl L. Butz, John Ehrlichman, Boyd Gibbons, Arthur Godfrey, W. Averell Harriman, A. Linwood Holton, Lady Bird Johnson, Henry Kissinger, Charles A. Lindbergh, Richard Lugar, Robert S. McNamara, Daniel P. Moynihan, William K. Reilly, Elliot L. Richardson, Sidney Dillon Ripley, Laurance Spelman Rockefeller, William P. Rogers, William Doyle Ruckelshaus, Donald Rumsfeld, Maurice H. Stans, Shirley Temple, Pierre Elliot Trudeau, Peter Edward Walker, George C. Wallace, Barbara Ward, and Caspar W. Weinberger.