[Technical Conference] IRAOO, International Association of Railway Operating Officers 1996 Sixtieth annual proceedings of the International Association of Railway Operating Officers 1996 : [1996 Technical Conference, Chicago, Illinois] 1995 Fifty ninth annual proceedings of the International Association of Railway Operating Officers 1995 : [1995 Technical Conference, Chicago, Illinois] 1994 Fifty eighth annual proceedings of the International Association of Railway Operating Officers 1994 : [1994 Technical Conference, Chicago, Illinois] 1993 Fifty seventh annual proceedings of the International Association of Railway Operating Officers 1993 : [1993 Technical Conference, Chicago, Illinois] 1992 Fifty sixth annual proceedings of the International Association of Railway Operating Officers 1992 : [1992 Technical Conference, Joint Meeting of the Coordinated Associations with the RSA, Chicago, Illinois] 1991 Fifty fifth annual proceedings of the International Association of Railway Operating Officers 1991 : [Chicago, Illinois] 1990 Fifty fourth annual proceedings of the International Association of Railway Operating Officers 1990