I had built a couple of rocking horses. I had even done a rocking motorcycle. So when I seen the plans for the "Rocking Iron Horse", I just couldn't resist.
The plans for this called for plywood. I never use plywood on anything. I absolutely hate plywood. If I'm going to take the time to build something, it's going to be out of solid wood. As for kid's toys, I never use paint. After enough years, even the best quality of paints chip or peel. I use stain. For durability on my toys, every part is glued, then screwed down into a countersunk hole which I then plug and sand down smooth.
This train is built from cottonwood. It is close to four feet long. It is also heavy. I find that to be a good thing for several reasons. First of all, solid construction is going to naturally make it heavy. Beyond that though, the heavier these rockers are, the less likely a child can get it rocking wildly enough to flip over on it.
By the way, in the bottom picture, that is my youngest son, William Calvin, sitting on it.