If it's the same vid that's been running around twatter, it was actually taken months ago. Tanks certainly aren't going to the border, though other equipment will.
It still serves a metaphorical purpose: we're doing something about the border. I'm sure there is a train with equipment on it heading to the border, just probably not as impressive as this one.
As an aside, they did mobilize to TX out of Ft. Carson earlier this year, IIRC, and they did have tanks (Ft. Carson is the 4th ID). Could be film from that.