A quick look at some of the free downloads available online. The sites mentioned, in order are -

1. Scalescenes.com (and Scalescenes modellers group on Facebook)
2. Hall-royd-junction.co.uk
3. Modelbuildings.org
4. Scenerybuilder.com
5. 3dk.ca
6. Wordsworthmodelrailway.co.uk
7. Craftrains.com