Chung line would be extended along the northern coast of Hong Kong Island, with Tamar, Exhibition Centre, Causeway Bay North and Fortress Hill stations along the route. The extension would then connect eastwards to the existing Island line at Fortress Hill station, and continue on the remaining Island line section to Chai Wan station. Concurrently, the Tseung Kwan O line would extend from its current westbound terminus at North Point station to the existing Island line at Fortress Hill station, and continue on the remaining Island line to Kennedy Town station. This scheme would greatly increase the number of stations reached directly by the Tung Chung line and the Tseung Kwan O line on Hong Kong Island, but east-west directional traffic along the existing Island line would be interrupted and require an interchange. In addition, the maximum train frequency between Fortress Hill and Chai Wan stations, which would be served by the Tung Chung line, would have to reduce by 8 trains per hour because the service frequency of the Tung Chung line is restricted by the capacity of the Tsing Ma Bridge. The signalling system and rolling stock used on both lines are also different, so the “swap” scheme was not considered in the plan. "Interchange" scheme Both the existing Tung Chung line and Tseung Kwan O line would be extended along the northern coast of Hong Kong Island. Three stations, namely Tamar, Exhibition Centre and Causeway Bay North, would be constructed along the extensions, and either Tamar or Causeway Bay North station would be chosen as an interchange between the two lines. This scheme would preserve the existing Island line in its current form and would not change the current commuting pattern between the Central, Western and Eastern Districts. However, as the Tung Chung and Tseung Kwan O lines would not be run on the Island line, passengers would still need to interchange as they currently do. Also, this arrangement would be less effective than the "Swap" scheme in relieving congestion, since although the number of stations and the area served has increased, the link with the current Island line would still be the same, unlike the "Swap" scheme. 2014 plan According to the "Railway Development Strategy 2014" document, the government opted for the interchange scheme because its construction cost and difficulties are lower and it does not interfere with the commuting patterns of current Island line users.