2. China Communications and Highway Engineering Bureau Group Co., Ltd. ..
3. China Railway 11th Bureau Group Co., Ltd. ..
4. China Communications First Bureau Group Co., Ltd. ..
5. China Railway Construction Engineering Group Co., Ltd ..
6. Institute of Tunnel Engineering, North China University of Water Resources and Hydropower.
7. Tunnel Design Institute of Beijing Traffic Planning and Design Institute.
8. Tunnel Design Institute of China Communications Highway Consulting and Design Institute.