Weight support of ping pong table

I have a 5x9 post war toy like layout on a heavy 200 pound ping pong table. I want 6x9 to do what I want to do. Do you think attaching plywood to cover the entire table and enlarge it to 6 x9 would be fine. Would it likely support weight of the plywood and train layout? I think it would as it is a heavy table but has anybody done something like that? Bedroom I use is only 11x11