If they were willing to spend that kind of money per gallon, water would not be a problem.
Yes, cost would be a factor. But, if you have NO water what are you going to do? Water purchased from a vending machine costs one dollar. I’m sure the cost of delivered rail water would be considerable less. But, that remains to be seen.
Water from sea water and pipe lines will be years down the road. Water by rail is not new. Arrowhead water until recently was delivered by rail to California processing plants. WBR is an emergency fix for those areas in need.