I caught the orange man talking on the radio, as I am not american I knew it was going to be something stupid but this? I thought it was a joke, an onion like thing, but nooooo. What sealed it is when in the very speech about the new 100x battleships, trump stated that he did not know why the us stopped using battleships....
I think they are trying to crack a joke.
Considering that the escape velocity on Earth's surface is ~11200m/s and railgun speeds tend to be around 5000m/s^[at least in Wikipedia, all stated values are < 5km/s] (i.e. less than half) and also that the escape velocity would be considering a normal direction whereas railgun usage tends to be more tangential (from the surface of the Earth), I wouldn't be expecting any casual leave-the-atmosphere scenarios.
As far as guided systems go, last I checked there wasn't enough leeway to add any electronic or mechanical elements in the projectiles.