What looks like an airplane or wind turbine propeller blade except it's huge, like 130 long is my guesstimate, being transported by train?

So I pull up to this railroad track and there's an entire train dedicated just to these light gray colored things that looked like huge propeller blades, except no plane in the world would have propellers that big. So then I think maybe they're wind turbines, except they aren't that huge either. It was like seeing something from outer space. I eyeballed them as they went by, in 10 ft increments and am guessing 130 ft long at least. One end would be a huge perfectly round opening and looked like it would attach to some type of hub, just like a propeller. It immediately widened into what looked like very wide leading/trailing edges, then gradually tapered off toward the other end. Any idea what it is? The curiosity is killing my cat.