The government invited the MTRC to build a train line, then known as the Lantau Airport Railway, to the airport. Construction started in November 1994, after the Chinese and British governments settled their financial and land disagreements. The new line was included in the financing plans of the new Hong Kong International Airport as the airport was not considered viable without direct public transport links. Construction costs were also shared by the MTRC, which was granted many large-scale developments in the construction plans for the new stations. The Lantau Airport Railway turned into two MTR lines, the Tung Chung line and the Airport Express. The Tung Chung line was officially opened on 21 June 1998 by Hong Kong Chief Executive Tung Chee-hwa, and service commenced the next day. The Airport Express opened for service on 6 July 1998 along with the new Hong Kong International Airport. The Airport Express also offers flight check-in facilities at Kowloon station and Hong Kong station—the in-town check-ins offer a more convenient and time-saving routine; a free shuttle bus service transports travellers from these stations to their respective hotels as well. Porters are also available to help transport luggage from and onto trains. It is the second most popular means of transport to the airport after buses. In 2012, it had a 21.8 per cent of share of the traffic to and from the airport. However, this has declined from a peak of 32 per cent in 1999. The Quarry Bay Congestion Relief Works extended the Hong Kong Island end of the Kwun Tong line from Quarry Bay to North Point via a pair of tunnels. The project was initiated due to overcrowding at Quarry Bay and persistent passenger complaints about the five-minute walk from the Island line platforms to the Kwun Tong line platform. Construction began in September 1997 and was completed in September 2001 at a cost of HK$3.1 billion. As with most earlier interchange stations, a cross-platform interchange arrangement was provided here in both directions. Construction of the Tseung Kwan O line (called the Tseung Kwan O extension line in the planning stage) was approved on 18 August 1998 to serve new housing developments. Construction began on 24 April 1999 and the line officially opened in 2002. It took over the existing Kwun Tong line tracks running through the Eastern Harbour Tunnel, so that the full line stretches from Po Lam to North Point. When the line was opened, the Kwun Tong line was diverted to Tiu Keng Leng on the new line.