Maglev trains use magnetic levitation to float above the tracks and move forward. They are very fast and efficient, but also very expensive to build. Vactrains are a type of maglev train that uses a vacuum tube to levitate and move the train. They are even faster than regular maglev trains, but are even more expensive to build. Hyperloops are a proposed type of transportation that would use a low-pressure tube to send people or cargo through a tube at high speeds. They have not been built yet, but could one day be a very fast and efficient way to travel.
Some of the emerging trends in Maglev Train, Vactrain, and Hyperloop include the development of magnetic levitation technologies, the use of evacuated tubes for high-speed travel, and the use of linear motors for propulsion.