1956 1, Su Min returned to China and was assigned to the Railway Research Institute of the Ministry of Railways to be responsible for the preparation of the vehicle research room, and served as the deputy director and director of the research room. Participated in the compilation of the Railway Science and Technology Development Prospect Plan, led all comrades in the Vehicle Research Office to strengthen close cooperation with brother units in accordance with the planning requirements, and successively carried out research on important vehicle parts and new overall structures, and achieved fruitful results. Participate in the formulation of the National Railway 12 Science and Technology Development Plan. According to the planning requirements, we will focus on solving the key technical problems that are urgently needed in current transportation production. Comrades who lead the vehicle research office have filled the gap in vehicle design in China and absorbed advanced experience from abroad. Through systematic research, they have completed the development of new products, such as freight car to 8 bogie, passenger car to 202 bogie, freight car coupler 13, C50 gondola car, etc., which have become the main products of China's railways and have been popularized and applied on hundreds of thousands of freight cars and buses. At the same time, he also participated in the formulation of technical policies for major industries in China (12), and put forward the demonstration of the development direction of railway vehicles, which was adopted. This project won the first prize of National Science and Technology Progress Award 1985.
During the period of 1964, hundreds of thousands of freight cars in China suffered serious axle burning accidents due to the end wear of nodular cast iron bearing shells. Su Min, the project leader, led a special team to study and solve this problem. After years of repeated investigation and experimental research, the "plastic tile head" was finally developed, which overcame the end wear of the bearing bush and reduced the shaft burning accident by 70%. 1977 passed the ministerial appraisal and was popularized in the whole railway. 1978 won the National Science Conference Award.
1979 with the intensification of the contradiction between railway transportation capacity and freight volume in China, it has become an urgent problem to develop new vehicles that adapt to the development of heavy-haul transportation. After repeated research and demonstration, Su Min proposed to the State Economic Commission and the Ministry of Railways to develop a shortened C6 1 gondola car with increased load per linear meter, so that the 5000-ton heavy-haul train can be within the effective station line length of 850 meters and the railway transportation capacity can be improved. After this suggestion was adopted, Qiqihar Factory designed and trial-produced a prototype car, and Su Min organized relevant scientific researchers to carry out various experimental research work, thus achieving the expected goal of running a 5000-ton heavy-haul train. The project passed the ministerial appraisal and won the third prize of national scientific and technological progress.
In order to fully popularize China's railway heavy-haul capacity expansion technology and solve the transportation shortage problem in China, Comrade Su Min led the heavy-haul capacity expansion test in 1982. For the first time in China, the loop line and main line tests with a weight of 5000-7000 tons (maximum 10000 tons) and the capacity expansion test of 25-30 passenger trains were carried out. It has promoted the smooth development of China's heavy-duty capacity expansion work and won the national "Sixth Five-Year Plan" award jointly issued by the State Planning Commission and the Science and Technology Commission.
In the early 1990s, he made suggestions for speeding up the railway. Su Min is also committed to the cultivation of talents in the vehicle industry. He was one of the earliest graduate tutors after the Cultural Revolution.