People need to get to places really fast sometimes because business or something it would be a convenient way to get there very quick. The train runs through a safe vacuum tube and the glass would be bulletproof it would be really safe no wrecks no deaths not of anything.
Why would you want to have something go that fast, particals moving at such high velocity make it time travel, and what if something is pressure goes wrong, they all get squished, what if it crasher, a hyper powerful explosion. And what if you fall of or are in front of it? It's easy, you die so fast your body vaporizes! Gee whiz that sounds like a whole lot of fun! And what if it can't stop in time, oh well, everyone died! Now lets let the remains of the vaporized bodies fly through the tube, hit other trains, and run into walls and explode, or mabye a split atom, YAY, now the world will end and we'll all die. YAY FOR KILLING EVERYONE WITH TRAINS!