Railway point drive unit with linear induction motor(s)

Linear induction motors (LIMs) 10a, 10b are used to drive point rails. To reduce frictional forces during movement, the switch mechanism can be levitated during operation. The motors may be three-phase motors, and may have ladder secondaries. 12a, 12b represent controllable power supplies; 14 is a controller, possibly a vital controller. The controller responds to feedback from at least one of: a controllable power supply; an LIM; a switch track; and a remote signal. Each LIM may include a ground-mounted primary inductor, and a switch track-mounted secondary. When the LIM is energized, the secondary is magnetically attracted to the primary, and is thus moveable relative to the magnetic field around the primary. The controllable power supply can include a solid state power converter having a controlled output voltage, which may employ a pulse-width-modulation scheme. The solid state power converter may have a variable voltage, and variable or fixed frequency. 24a, 24b represent clamp means. A spacer may be used between each motor primary and secondary.