I have been searching for a container crane for years.
www.searails.com sells or used to sell a model in N-scale. When I was checking it out, it was only available as a RTR model made to order.
I wanted my crane to be as detailed as possible since it goes in the front of my layout. Now I decided to scratch build my own crane with Plastruct ABS and photo etched pieces.
It will not be true N-scale since I build it in 1:200 scale. Most photo etched detail parts are 1:200 and it is pretty big in that scale as well.
Here is a drawing with a container as comparison.
I used a modern Kalmar crane for my drawing.