Construction work progresses on Panama Metro Line 3 under water tunnel, Panama October 16, 2025 | Latin America News, News Panama Metro has confirmed that the tunnel boring machine (TBM) building the 4.5 km underwater section of Line 3 has crossed beneath the Panama Canal’s navigation channel. Excavation work is 45 percen... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password