With the rapid development of domestic rail transit, the demand for construction financial support will be very large. The number of operating railway lines is increasing, and consequently, the demand for operation and maintenance funds will continue to increase. Determining how to facilitate the sustainable development of rail transit is an immediate problem. After 150 years of development, Japanese railway companies were able to achieve profitability. Taking the Tokyo metropolitan area as an example, this study analyzes the operation status and development path of three-level rail transit enterprises and finds that developing related businesses is the key to the sustainable development of Japanese rail transit. Through an analysis of the business form and profit status of the businesses of Japanese railway companies, this study finds that Chinese rail transit can develop related business through the three stages of ‘real estate, retail and service, diversified business’, and combine this strategy with the Japanese business model of sustainable development.