Maglev trains do not have zero friction. Although maglev trains use magnetic levitation to significantly reduce rolling friction, they still experience other types of friction, including aerodynamic drag and friction between the guideway and the train's levitation system.

Aerodynamic drag: As a maglev train moves through the air, it experiences aerodynamic drag, which is the resistance of the air to the train's motion. This type of friction increases with the train's speed and can be significant at high speeds.

Friction between the guideway and the train's levitation system: The levitation system of a maglev train uses magnetic forces to lift the train off the guideway, reducing rolling friction. However, there is still some friction between the guideway and the train's levitation system, caused by the interaction between the magnetic fields and the materials used in the guideway and the train's levitation system.

Overall, maglev trains have significantly reduced friction compared to conventional trains with wheels and rails, but they do not have zero friction.