Recent findings at the construction site of the Yinba Railway (Baotou-Yinchuan High-Speed Rail Yinchuan-Bayanhot branch) revealed potential quality issues with rubber materials used in bridge construction by China Railway 16th Bureau Group, a subsidiary of China Railway Construction Corporation Limited (601186.SH). Randomly sampled ethylene propylene diene monomer (EPDM) rubber sheets, already installed in multiple locations, were easily cut and torn. Laboratory tests confirmed their core performance metrics fell far below standards, and the primary material was not EPDM rubber as specified. Experts warn that such substandard materials could compromise bridge longevity and pose safety risks for rail operations.
The EPDM rubber sheets were installed between concrete cable troughs and steel crossbeams on both sides of the railway to distribute pressure, absorb vibrations, and provide waterproofing. On-site tests showed the sheets could be effortlessly sliced with a knife, and the torn edges exhibited rough, granular textures—unlike the smooth finish typical of genuine EPDM products. Further lab analysis of a sample revealed a tensile strength of just 1.78MPa, merely 15% of the required ≥12MPa standard, and identified the material as isoprene rubber, which has inferior weather resistance compared to EPDM.
When questioned, project manager Zhang Guojun of China Railway 16th Bureau admitted limited familiarity with the material but defended its use, citing passing batch inspections. Procurement records showed ~25,000 EPDM sheets were sourced from a Hengshui-based supplier, with three batches (9,000 sheets) delivered and reportedly passing spot checks. However, the third batch’s inspection report—showing a tensile strength of 14.1MPa—contradicted the journalist’s test results. Zhang stated the team relied solely on inspection reports for approval, while the on-site supervisor, Chi Jinfu from Gansu Xinda Construction Consulting Co. (a subsidiary of China Railway Lanzhou Group), asserted the inspection process was compliant.
Notably, the procurement contract explicitly prohibited recycled rubber and mandated manufacturer logos for traceability, yet some installed sheets lacked identifying markings. Industry experts cautioned that substandard EPDM sheets could accelerate structural degradation, creating long-term safety hazards.
China Railway 16th Bureau pledged to replace non-compliant materials if confirmed and seek compensation from the supplier. No response was received from the parent company’s chairman, Wu Yankun, by press time.
Comments