Some of these ideas have been around since I was a kid....the Tower of Terror ride at Dremworld (Gold Coast Australia- bout 50 klms from me) is powered by a electro magnets set in sequence under the rails, it accelerates the carriage to a speed to climb the tower...sort of based on the Rail Gun idea. In a vacumm situation such as space, it would probably be possible to reach the speed of light..the speed electricity travels at.. (as long as nothing gets in the way
) G-forces at acceleration would probably turn you to mush if it was done at, or over a short distance...the ultimate thrill ride.
If you were to use it to launch in an atmosphere, something like a lightning bolt would have to preceed the launch item to create a vacumm to travel in...otherwise bursting into flames from friction can be a problem