This is what happens when I get distracted. I can come up with a whole raft of ideas on a totally new project. Here is a third version of the nuclear flask layout that I'm quite taken with.
Once again its a strange shape so that I would be able to watch the trains come towards me and the crane is tucked away at the back so that I could make it work in one of my "Heath-Robinsonish" non-electrical ways. The idea of making a working gantry crane like this one of the factors that keeps driving me on this particular concept and is something that I could incorporate in many other layouts. On a small layout such as this some kind of working feature would be vital. One of my Gn15 layouts "Whinny Lane" had a working crane and when ever I stopped to load and unload a train with the crane a large crowd always gathered.I have also suggested a lorry and flatbed trailer alongside the crane so that the loading and unloading of the flask would have purpose. Sections of disused trackbed, a derelict signal box and goods shed that has seen better days would help add some atmosphere to this little model.
Now to devote some serious thought to how to make the crane work.