Shanghai Rail Transit Line 5 has been the first in the world to implement the renovation, expansion, and extension construction of an entire in-service line. At the end of 2018, after two and a half years of construction, the updated Shanghai Rail Transit Line 5 was opened along with the south extension project of Line 5, which was of great significance for the improvement of the overall operational performance of Line 5. Ensuring the normal and safe operation of the existing line during the reconstruction period was a challenge. Extensive cooperation was required between the designer and the client, construction, operation, and maintenance teams, to formulate reasonable principles, schemes and project implementation plans for the renovation and expansion construction efforts. This approach not only laid the technical foundation for the achievement of the first renovation and expansionof an entire in-service elevated rail transit line in China, but also provides a reference for similar projects in the future. Furthermore, according to the newest rail transit service standards, a reasonable technical improvement and upgrade plan was proposed for the existing line, resulting in a better overall performance, better alignment with the urban environment, and more customer-friendly design concept for Line 5.