Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

This engine and boiler are built to a design by Jan Gunnarsson and the plans for them were serialized in Live Steam magazine many years ago.
You can still get the complete articles' and plans in the book "Steam and Stirling engines you can Build" (volume one) which is available from Village Press. 

https://secure.villagepress.com/store/items/detail/item/847