Tutorial for a Allan/Stephenson steam locomotive distribution

Hi there,

I'm looking for a tutorial to build up a complete and working Allan/Stephenson distribution for steam locomotives.
Some ideas where I can find it?
For the Walschaert/Eusinger distribution I use normally the Paul Hobbes tutorial and I feel it's a good made one, but I cannot find such a tutorila for Allan/Stephenson one.

Best Ettore48