The Kwun Tong Line was extended across the harbour on 5 August 1989 to Quarry Bay Station , which became an interchange station for the Kwun Tong Line and the Island Line .
The Kwun Tong Line was extended across the harbour to Quarry Bay , which became an interchange station for the Kwun Tong Line and the Island Line . The extension was launched on 5 August 1989 .