Objective To address issues such as long lead times for imported spare parts, poor coordination of electro-pneumatic hybrid braking, and the lack of health management equipment in existing Tianjin Metro Line 1 (hereinafter referred to as Line 1), it is necessary to perform an autonomous and intelligent upgrade of the braking system.

Method The train braking system modification scheme of Line 1 adopts a replacement strategy using localized key components, including core equipment such as air supply systems, brake control units, and auxiliary control boxes. On the basis of maximizing the retention of original interface forms, an adaptation and optimization work is carried out in combination with engineering feasibility. The system control architecture is upgraded from traditional hardwired control to a redundant architecture, with network control as the primary mode and hardwired control as the backup. Health management functions are added to the braking and air supply systems respectively, enabling fault alarming, performance early warning, and lifespan management.

Result & Conclusion  The modified air supply system can realize the collection and monitoring of key parameters and possesses comprehensive health management capabilities. The brake control unit adopts an integrated design with complete functions and easy maintenance. By optimizing the switching speed points between the electric braking and pneumatic braking, the effectiveness of electric braking is fully utilized, and the brake shoe wear is reduced. After the application of the autonomous and intelligent renovation scheme on trains of Line 1, relevant trains have successfully passed third-party type tests, a 5 200 km empty-load operation assessment, and a 450 000 km passenger operation assessment. The braking system operation is stable and reliable, and can significantly reduce O&M costs and improve the line operational efficiency.