The metro system was supposed to have two lines. Chen Yu planned for a north-south line and an east-west line. The plans for these lines are very similar to Line 1 and Line 2. The east-west line was never built. The north-south line was supposed to be built by Project Nine. There wasn't enough time, money, or materials so instead of having a subway, they planned to use trolleybuses. The tunnel was finished in 1966 but it could not be used. This was because there was an unsafe section of the tunnel. There were many attempts to restart Project Nine in the 1970s, but none of these attempts restarted Project Nine.