Trials underway on Northern Section of Tianjin Metro Line Z4, China October 11, 2025 | Asia Pacific News, News The first phase of Tianjin Metro Line Z4 has begun an empty-load trial run on its northern section, covering 10 stations. The northern section spans 22 km, connecting Hangu Street, the Sino-Singapore ... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password