The electromagnetic suspension was, proposed by Graeminger in the 1930's. In the 1970's, Germany started development of this approach, which has resulted in the Transrapid System (see Maglev in Germany). The suspension is inherently unstable because, as the gap between the electromagnet and the iron sheet decreases, the attractive force increases. However, the suspension can operate stably by continuous servo control of the winding current in the electromagnet. If the gap between the vehicle electromagnet and the guideway iron sheet above it decreases, the current in the winding on the electromagnet is reduced, reducing the attractive force. If the gap between increases, the current is increased. This current is servo controlled on a time scale of a few thousandths of seconds. The electromagnetic suspension was, proposed by Graeminger in the 1930's. In the 1970's,

Although the electromagnet approach eliminates the high cost of permanent magnets on the guideway, the problem of very small gap between the vehicle and the guideway remains. In the Transrapid System, the gap is 3/8th of an inch. Because of the narrow gap, the guideway construction and maintenance tolerances are extremely tight which substantially increases cost. In addition, ensuring adequate clearance under various environmental challenges, such as ice and snow buildup, earth settling, earthquake movements, and thermal expansion due to temperature changes is difficult.