Roughly 8,000 pieces (including all the plates in the back to make it solid, and thus stable- unfortunately, about 25% of it doesn't show because it is covered up by Tim Caffery's rather lovely brick-built mountains!)
About this creation
Like the Pointillist Mosaic, this is a mosaic used as background at the 2006 NMRA show in Philly. Also like that one, I took no photos of this mosaic myself, so I will give photo credits where due (the main photo belongs to Phillip Thorne).
Here is a nice shot (photo due to Arthur Stromberg), from an angle, showing off the background mosaic situated between Tim's mountains, with various mountain type vehicles (built by Tim and Jim Foulds) in the foreground.