The Single Resilient System (SRS) e-Clip assembly is a bolt-free, shoulder-free elastic clip fastener. It uses aφ20mm single-toed PR spring clip as the buckling part. The buckling pressure is generated by the elastic deformation of the single-toed spring clip. The buckling pressure of the single-toed spring fastener is 13～15kN/group, the buckle pressure is stable and will not be affected by the loosening of other parts of the fastener, thereby improving the safety of subway operation.

The Single Resilient System (SRS) e-Clip assembly provide lateral distance adjustment through the occlusion between the gauge block and the iron backing plate. The fasteners have the functions of distance adjustment, shock absorption, noise reduction, insulation and spring stop, which are widely used in Guangzhou Metro.