Yes, it certianly is 15" gauge, I took the photos from the normal height of a 5inch scale person (30 inches) to achieve the realism. All the buildings are built to 5 inch scale, and all the roofs come out to about 6 feet tall. Most of the major shop space, like our roundhouse has sunken floors to compensate for the shortened height.
We use actual special-cast 5" scale spikes, driven in with a carpenter's hammer. Alot of the major castings are done in a specialty Iron Works in southern california. We use 12# rail also. We also use 12X12X4 ties, and they're good for 30 years!
Our route is 1.25 miles long plus a small yard, the mountian division, a couple of passing sidings and a long spur to our gravel hopper and maintenence train shed. If you have any more questions, let me know.