In the Chongqing Rail Transit Interconnection Project, we have rationally planned the cross-line stations and inter-line interconnection lines, based on the physical construction of Lines 4, 5, 10 and the loop line, and unified the basic conditions of lines, boundaries, power supply, communication, etc.; at the same time, combining special topographic features of the mountainous city, we have unified standard vehicle model design for As trains; and established the global scheduling system, standardized PIS, guidance and other passenger service systems to match the needs of co-line and cross-line operation for trains; finally, we have developed the signaling system with independent intellectual property rights, and constructed the full lifecycle management system for interconnection project planning, design, construction and operation, based on the core of setting up the "Interconnected CBTC System". As for the interconnection project, we have obtained a number of achievements of independent intellectual property rights and 38 invention patents, published 30 academic papers and 2 SCI-included papers, and issued 1 white book for construction guidance. Two local standards and one industry and group standards were promulgated Up to now, interconnection technology has been promoted and applied to a total of 53 lines in 25 cities in China, and the project value obtained has reached RMB 17.611 billion yuan. At the end of 2021, the results of the project would go abroad for the first time and be applied to Hanoi Metro in Vietnam, actively contributing to the "Belt and Road" initiative. China Association of Metros selected this project as the "Special Prize of Urban Rail Transit Science and Technology Progress Award". In December 2021, three lines of Chongqing rail transit "Line 4 - Loop Line - Line 5" officially realized cross-line passenger carrying operation, saving 33 minutes of travel time for one-way trips, providing citizens with more convenient and faster travel services.