The rolling stock industries have mainly been formed of the industrial sectors engaged in manufacturing rolling stock, electric equipment and mechanical components, supported by a wide range of other sectors such as producing materials, manufacturing commodities, providing distribution and logistics, and supplying maintenance services.

On the other hand, the collaboration between railway operators and manufacturers of rolling stock, and related equipment and parts is indispensable, because of that rolling stock can be said a key hardware in total railway system.

In taking the above facts into consideration, JARi is organized of the members, the associate members, the designated members and then the individual members, as described below:

　　　Member 　　　　　　 : manufacturers of car body and building rolling stock,
　　　　　　　　　　　　　 　 electric equipment, and non-electric equipment or parts.

　　　Associate member　 : manufacturers of commodities, suppliers of materials,
　　　　　　　　　　　　　　　providers of maintenance services, distribution and logistics,
　　　　　　　　　　　　　　　and other firms related to rolling stock industries.

　　　Designated member : JR, private railway and local government owned companies.