The Tate's Cairn Tunnel Co Ltd (TCTC) was awarded the franchise of 30 years to build and operate the Tunnel in 1988. The Tunnel will be transferred to government after the franchised period. The Tate's Cairn Tunnel is a rock tunnel of 4 kilometres long. It is the longest road tunnel in Hong Kong.
The Tunnel walls are constructed with 300 - 500mm concrete lining with paint coated. The Tunnel links the southern part of the NT and eastern part of Kowloon at Siu Lek Yuen and Diamond Hill. It was opened to traffic in 1991 after three years' construction. The Tunnel is of dual tube configured, which contains 4 traffic lanes. Together with about 4.5 kilometres approach and exit roads, the Tunnel Control Area covers totally 8.5 kilometres of tunnel, bridges and roads. In addition, there are 7 service buildings including the Administration Building, four ventilation buildings and two portal equipment buildings.
The Tunnel also forms part of the Route 2 linking the traffic from Shatin through Tate's Cairn Highway to Hong Kong East through Kwun Tong Bypass and the Eastern Harbour Crossing.
