Powerful electromagnets are fitted on top of guideways either ttract or repel the magents fitted on the bottom of train. The froce of attraction/repulsion rasies the train in hovering position.
Explanation:
Magentic fields exist between two opposite/like poles. The poles do not have to be touching each other. They can be separated by a distance in a medium that doesn' block magnetic field.
In magelv train the magnetic forces between two poles are used to operate the train. The two poles are separated by train body and air.
The force between two charges is directly proportional to the amount of charges at the two points and inversely proportional to the square of distance between the two points.