Lots of interesting information and links. Lists miniature railways around the UK with track plans.
Extract from Home page of website
What is a "Minor Railway"? As far as this Website and the book Minor Railways is concerned a "Minor Railway" is a Standard Gauge Railway, Narrow Gauge Railway, Miniature Railway (7¼" gauge or greater & ground level), Tramway or Cliff Railway - which offers rides to the general public and is operated mainly for leisure purposes. The range of such railways is enormous - from the Severn Valley Railway and the Ffestiniog Railway, to railways in theme parks, garden centres, zoos and small circuits of track operated by local a Model Engineering Society. It is true to say the range of "Minor Railways" is so wide, that the only thing they have in common are wheels running on rails!

Lots of interesting information on this website

The Railway Club Directory lists all Traditional Railway Societies. For ease of locating and reading, these are divided into 5 categories:

(1) National railway societies and clubs

(2) Specialised national railway societies

(3) Historical railway societies

​(4) Local railway clubs

​(5) UK based international railway societies