For Your Geographers: GeoCommons.COM
GeoCommons is the public community of GeoIQ users who are building an open repository of data and maps for the world. The GeoIQ platform includes a large number of features that empower you to easily access, visualize and analyze your data...
...You can watch any of our videos to learn more, or just sign up for free to get started building your own maps.
Selecting Maps and searching for UK there are 15 pages of user created maps. Selecting Rail and zooming in: