The International Heavy Haul Association, Inc. (IHHA) is a non-profit, non political entity organized to facilitate and participate in he development or acquisition and distribution of knowledge germane to heavy haul railroad technology and operations. Membership is open to any heavy haul railroad regardless of country of origin. A heavy haul railroad is defined as one that meets at least two of the following requirements:
Regularly operates or is contemplating the operation of unit or combined trains of at least 5 000 metric tons.
Hauls or is contemplating the hauling of revenue freight of at least 20 million gross tons per year over a given line haul segment comprising at least 150 km in length.
Regularly operates or is contemplating the operation of equipment with axle loadings of 25 tons or more.