<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>a11r</author><text>I am assuming that you are talking about the thermal expansion of the tubes (ducts ?).  A long time ago, the rails making up train tracks used to have gaps every few meters to accommodate thermal expansion (same problem). Modern rails in high speed train tracks are welded into one continuous bar that can be over a kilometer long. The trick is to stretch the rail just enough and then pin it down - kind of like a slightly stretched rubber band. That stretch can accommodate thermal expansion.</text><parent_chain><item><author>lisper</author><text>Ooh, how I wish I could buy put options on the Hyperloop.  Because unless they solve the thermal expansion problem -- and there is no feasible solution on the horizon AFAICT -- they will fail.</text></item></parent_chain></comment><story><title>Hyperloop One Raises $50M, Hires Former Uber CFO</title><url>http://www.bloomberg.com/news/articles/2016-10-13/hyperloop-one-raises-50-million-hires-former-uber-cfo</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>lnanek2</author><text>What&amp;#x27;s unsolvable about it? Every bridge I&amp;#x27;ve ever been on has had a little gap for expansion. Just make a little gap every 5km, cover the outside with rubber that stretches across the two sides, boom, you are done. The cars float on a little air pressure cushion and don&amp;#x27;t normally use their wheels, so there wouldn&amp;#x27;t even be a bump.</text><parent_chain><item><author>lisper</author><text>Ooh, how I wish I could buy put options on the Hyperloop.  Because unless they solve the thermal expansion problem -- and there is no feasible solution on the horizon AFAICT -- they will fail.</text></item></parent_chain></comment><story><title>Hyperloop One Raises $50M, Hires Former Uber CFO</title><url>http://www.bloomberg.com/news/articles/2016-10-13/hyperloop-one-raises-50-million-hires-former-uber-cfo</url></story>