One of the most valued and important entity nowadays is time. To help the people around the world to save their   travelling time, Elon Musk came up with an innovative idea of hyperloop. Hyperloop is a proposed mode of passenger and freight transportation that would propel a pod-like vehicle through a reduced-pressure tube that could potentially exceed airliner speeds. The pods would accelerate to cruising speed gradually using a linear electric motor and glide above their track using passive magnetic levitation or air bearings. The tubes could also go above ground on columns or underground, eliminating the dangers of grade crossings. It is hoped that the system will be highly energy-efficient, quiet, and autonomous. The concept, created  in 2012, incorporates reduced-pressure tubes in which pressurized capsules ride on an air cushion driven by linear induction motors and air compressors. The Hyperloop concept has been explicitly open-sourced by Musk and SpaceX, and others have been encouraged to take the ideas and further develop them. Also  a few companies have been formed, and several interdisciplinary student-led teams are working to advance the technology.  Lots of efforts are put to create this innovative  concept but it does surely has a limitation which is that  hyperloop is too susceptible to disruption from a power outage or terror attacks to be considered safe. The major reasons why it is difficult to operate high speed vehicles is due to presence of large amount of drag force or air resistance. This resistance becomes substantial when the vehicles reach high speeds. The vactrain (vacuum train)  concept theoretically eliminates these obstacles by employing magnetically levitating trains in evacuated (airless) or partly evacuated tubes, allowing for speeds of thousands of miles per hour. The hyperloop operates at a pressure of one millibar or 100Pa of pressure.

2   Some critics of Hyperloop focus on the experience—possibly unpleasant and frightening—of riding in a narrow, sealed, and windowless capsule inside a sealed steel tunnel, that is subjected to significant acceleration forces; high noise levels due to air being compressed and ducted around the capsule at near-sonic speeds; and the vibration and jostling. Even if the tube is initially smooth, ground may shift due to seismic activity. At high speeds, even minor deviations from a straight path may add considerable buffeting. This is in addition to the obvious practical and logistical questions regarding how to best deal with equipment malfunction, accidents, and emergency evacuations.     Here are the four main features of the hyperloop

  1. The passenger capsules aren’t propelled by air pressure like in vacuum tubes, but by two electromagnetic motors. It is aimed to travel at a top speed of 760 miles per hour. 3
  2. The tube tracks do have a vaccuum, but not completely free of air. Instead, they have low pressure air inside of them. Most things moving through air tubes will end up compressing the air in the front thus, providing a cushion of air that slows the object down. But the hyperloop will feature a compressor fan in the front of the capsule. The compressor fan can redirect air to the back of the capsule, but mostly air will be sent to the air bearings. 4
  3.  Air bearings are ski like paddles that levitate the capsules above the surface of the tube to reduce friction. 5
  4. The tube track is designed to be immune to weather and earthquakes. They are also designed to be self-powering and unobsrtuctive. The pillars that rise the tube abobe the ground have a small foot-print that can sway in the case of an earthquake. Each of the tube sections can move around flexibly of the train ships because there isn’t a constant track that capsules rely on. The solar panels present on the top of the track  provide the periodic motors with power.   6