This is something that our Space-Friends, the Pleiadians already have; they used it very effectively against in invading fleet of Reptilians fairly recently. It is also something that the US Military has been working on for some time; particularly, the US Navy.
The issue is how to generate enough electrical power to create the repellor forces needed and how to regenerate the power quickly. Ideally, the rail gun would be able to fire a projectile within 5 seconds. In an attempt to reach this rate of fire, Rail Guns can only be deployed on ships that can generate lots of power; think nuclear powered.
Ok. So, what can I do to help with this weapon and why would I help? Second first. As I have already stated, the Pleiadians have taken on the Reptilians on behalf of Planet Earth, but that was in self-interest as they have nine nearby planets that are peopled with Humans. Rail Guns are a very effective weapon for Space and other kinds of warfare and I like the idea of Earth being able to defend itself.
How can I help? Magnetism has a multiplier; the repellor force can be dialed up without using any additional primary motive electrical power. In another area, my no-moving parts electrical generator (described elsewhere on this site) is much more efficient at generating large amounts of Amps than any known generator. Once the power starts flowing, it continues without any additional work; each generator is an over-unity device that taps into the Zero-Point-Energy or, for you meditators, the Still-Point field.
There is another page on this site that describes a new Coil alloy that replaces wrapped copper wire. It too, is much more effective than wrapped copper wire and would make the Rail Gun lighter and more efficient; perhaps to the point that it could be mounted on an all-electric tank.