Not only are high-speed trains possible, they already existed. The train systems in Europe in Japan are light years ahead of the systems here in America. I think if America were to put more funding in such systems, it would prove to be a beneficial thing to many people who commute.
They are already happening, I don't understand the question as to whether or not they even can be effective. Japan has building and using high speed trains for decades, and there are a number of others in Europe and in Asia that are already happening - we just don't build them in the US.
High speed rails have been proven to be possible in Asian countries, and the science supports the expansion of the industry. Although the technology is not developed in the most efficient way possible, currently, the plans are certainly feasible and could be enacted to day barring any fiscal constraints. The several plans existing for high speed expansion are grounded in realistic and existing technology.
I am sure China is using them already, maybe Japan too. Some European countries might have them. They are very possible, maybe a little expensive. It could be worth it in the long run though. The US has to have the worse transportation system out of all the developed countries. I guess we just like our cars to much. If people want to solve gridlock, they might want to invest in more things like high speed rail.
yes, I do think that it is possible to make a train that can go a really high rate of speed. The problems is that a train going this fast when wrecked is going to kill every single person that is on it and it is going to be awful.