About raising hotel room tax:
•  16.5% would be among the highest: what are the higher ones and where are they?
•  If it would result in the more dollar-conscious tourists not coming, that would be a good thing. We've already surpassed our tourist carrying capacity.

Solution to how to raise even more money for  rail:
•   Don't do it. 
•  Only use what you've got and switch to the cheaper, more flexible BRT. 
https://www.itdp.org/library/standards-and-guides/the-bus-rapid-transit-standard/what-is-brt/