The second key invention of Drs. Powell and Danby is the Linear Synchronous Motor (LSM). The guideway has a set of LSM windings that carry a small alternating (AC) current, e.g., several thousand amp turns. The AC current is supplied from a conventional electrical power grid. When energized, they produce a traveling magnetic wave that pushes on the vehicle, overcoming whatever drag forces are acting on it. In effect the vehicle "rides" the AC LSM wave much as a surfer rides a water wave. It moves at the same speed as the LSM wave. The speed is determined only by the frequency of the AC power fed into the guideway. The maglev vehicles maintain a constant separation distance between them regardless of variations in head or tail winds, up or down grades, etc. acting on individual vehicles. Constant separation is very important for safety. The vehicle is easily controlled by adjusting the frequency of the LSM AC power wave.

High energy efficiency of the LSM propulsion system is achieved by not continuously energizing the entire guideway. Instead, only the local block of guideway on which the vehicle travels is energized. The length of the energized block is typically several hundred feet. When the vehicle leaves the energized block, LSM power is electronically switched to the next block and the old block is switched off. In this mode, LSM efficiency (propulsion power/input electric power) is over 80%.