A proposed tunnel between the UAE and India could take rail travel to a whole new level, quite literally, if the National Advisor Bureau (NAB) of the United Arab Emirates (UAE) has its way. The NAB is exploring the possibility of a 2,000 km long underwater rail tunnel to connect Fujairah with Mumbai. At a UAE-India conclave in Abu Dhabi, NAB said this line would facilitate the movement of people across the Arabian sea and feature pipelines for oil and water. The speed of the trains to be operational would be 600 to 1,000 km per hour. The 1,826 km distance between Mumbai and Fujairah could be covered in less than four hours, while the distance between Fujairah and Gwadar port could be covered within an hour. Creating a vacuum inside the tunnel will allow for a high-speed rail system as a result of reduced air resistance. The tunnel's concept is based on the Hyperloop technology. The Hyperloop is a proposed high-speed transportation system in which specialised pods are accelerated through a low-pressure tube to achieve speeds near the speed of sound. Earlier efforts at creating an under-sea hyperloop include Maritime Research Institute Netherlands (Marin) testing a model trans-Atlantic underwater tunnel between the United States and Europe capable of supporting hyperloop. The testing was done to check how the tunnel responds to wave action. This testing was to determine if the pods would be safe to travel under real oceanic conditions. The research concluded saying that this mode of transportation could be way less polluting that air travel and constant efforts are being made to bring this concept to life. Virgin Hyperloop also conducted trials, being the first to have a human passenger. The ride reached a speed of 150 km per hour but in a vacuum sealed tunnel, it is expected to reach a speed of 966 km per hour. The floating underwater tunnel would consist of two curved concrete tubes, submerged below the surface of the Arabian Sea. The submerged tubes would be stabilised by being attached to pontoons on the surface of the sea or by vertical tethers to the seafloor. Image:  Two curved concrete tubes, submerged below the surface of the Arabian SeaA provision would be made for enough gaps between the pontoons to allow ships to pass through. The tubes would be placed underwater, deep enough to avoid water traffic and weather. The tunnel would be watertight, resistant to seawater damage and able to withstand the hydrostatic forces acting on it. NAB said that the project awaits a feasibility study as an underwater rail tunnel held by floating pillars can pose unique challenges, and several aspects of it need serious consideration.Image: If realised, the tunnel would be another step in undersea hyperloop travel that has been a subject of much research in Europe and the United States. Also read: Virgin Hyperloop hosts its first human ride