Very interesting.. I had read about the rail gun earlier and see that it has promise.
But in my opinion, it may only be truly effective against stationary targets or targets that are manned. Many of today's missles have avoidance guidance built into them which would make a real chore for an uncontrollable missle like this to knock down.
They did say that it would be the end of the decade before it could be deployed. That seems an awfully long time to me and surely Russia will come up with some active defense means that they can/will sell to the Taliban, et al by then..