Objective Compared with the original air springs, the domestically-produced air springs （hereinafter referred to as domestic air springs） used on Guangzhou Metro Line 5 vehicles exhibit a deficiency of low load-bearing internal pressure （hereinafter referred to as load pressure）. A low load pressure will result in insufficient braking force output from the braking system, which in turn leads to train overrun faults. Therefore, in-depth research on this issue is necessary.

Method The specific low load pressure issue of the domestic air springs used on Guangzhou Metro Line 5 vehicles is presented, and the target for adjusting the load pressure is proposed. A technical approach is put forward to enhance the load pressure of the air springs by optimizing the structural parameters of the airbag cord. Accordingly, ten airbag variants with different cord parameters are trial-manufactured. The load pressure performance of the air springs under the ten airbag schemes is compared with that of the original ones. Scheme 10, demonstrating test parameters most consistent with the original, is adopted as the final optimized solution. Key performance indicators of the optimized air springs are verified experimentally.

Result & Conclusion  Compared with the original air spring, the optimized domestic air spring achieves an increase of 0.8 % in internal pressure under light-load conditions and 2.8 % under heavy-load conditions. It can not only meet the requirements of TB/T 2841—2019, but also satisfy all performance requirements for design and operation.