United Kingdom
National Railway Museum searchable archive
Narrow Perspectives - useful photo site with many detail pictures
Narrow Gauge Heaven - website dedicated to NG railways around the world, emphasis on the U.K.
The Railways Archive - massive searchable online archive
The corrugated Iron Club, history and uses of corrugated iron including building drawings.
Slate Industry of North & Mid Wales, Dave Sallery site with a mass of photos of the industry
The Lochaber Narrow Gauge Railway
Republic of Ireland
Mainland Europe
North America
Asia
Darjeeling Himalayan Railway Home website
Wikipedia - Darjeeling Himalayan Railway
South America
Africa
Australasia