Magnetic levitation

Magnetic levitation trains or maglevs are floating vehicles that are supported either by electromagnetic attraction or repulsion. They were initially conceptualised in the early 1900s, and have been in commercial use in some form since 1984. Maglev trains remove friction between the wheels and the rails, allowing for much higher speeds, reducing operating costs from fewer moving parts and rolling friction. In turn this means the main driver impeding forward movement becomes air resistance, driving technology development. They can also improve safety and prevent derailment. Further, they allow for wider trains to be built, increasing convenience; and they reduce the need for civil engineering projects as they can operate on higher inclines (of up to 10%) than traditional trains.
Two key technology areas are currently deployed: (i) electromagnetic suspension (EMS), which harnesses the attractive forces between magnets on the train's side and underside and on the guideway; and (ii) electromagnetic suspension systems, where magnets, generally placed in the undercarriage of the train, repel the train from the guideway, which allows for higher levitation. These are generally based on superconducting and supercooled technology systems. The need to build dedicated infrastructure from scratch, bypassing conventional infrastructure, and high capital expenditures remain obstacles to further deployment.