For many years now, the local government here has been trying to get "Mass Transit" going to alleviate the traffic problems. We have one main freeway leading into and out of downtown Honolulu. It is also the only main freeway going into and out of Western Oahu (SA2 can comment more on that). The push to get "Mass Transit" has included proposals for rail. The government has gone so far as to set in motion an increase in our general excise tax to fund a "Mass Transit" program. We still don't know what kind of system will be used - because no one has decided yet. The local government needs to show the federal government that they're serious about it this time so we can get federal money too. The last time I remember rail being mentioned was sometime in the 90's. If I recall correctly, one of the big concerns against rail was how it would make "our island paradise" too urban. The thought of a raised track blocking someone's access to their view of the ocean... I don't know if we're ever going to get rail here (or whether we really need it). It was a struggle just to get our most recent "interstate" road up (environmental and cultural concerns). And even though it's doable, I couldn't imagine the effort it would take to get undersea tunnels up between the islands.
When I was in Japan on two one-week periods last year for work, I was impressed by the train systems there. We never had to wait long for the train to arrive to take us from Yokosuka to Shinagawa then transferring to head into Tokyo. Very frequent. Once in Tokyo though, you could see that tracks were everywhere and things got very ... compressed. I don't see our state having anything but a token rail system.. there just isn't enough available land in the areas where you need to go to.
Sure there is enough land in the contiguous 48, but if I don't fly, driving is much more fun. It was fun even driving from Las Vegas to the Grand Canyon, which was the longest drive I've ever done behind the wheel.
