They assert that the urban agglomeration in south Oahu is ideally suited to rail as it is constrained by mountains to a narrow strip along the coast , which will be well served by a single rail line .
Which has the fourth highest population density in the US .
They assert that the urban agglomeration in south Oahu is ideally suited to rail as it is constrained by mountains to a narrow strip along the coast , which will be well served by a single rail line and which has the fourth highest population density in the US .