Save Land:As the city's urban land values in general high, built in the underground railway, you can save floor space, so that the ground site may be used for other purposes;
Reduce noise:Railway was built in underground, can reduce the ground noise.
Reduce interference :As the subway on the routing is not with the other transport systems (such as surface roads) overlap, cross, therefore less interference with vehicular traffic being can save a lot of commuting time.
Energy Conservation:In the global warming problem, the MTR is the best public transport. MTR speed stability, a substantial saving in commuting time, so that people willing to travel, but also to replace a lot of the energy consumed by car.