This is an inspection car. The right side is for the "brass", while your Great Grandfather is at the controls of the small steam locomotive. The car is likely powered by a small vertical boiler, as the car would run alone and great power wasn't needed. There was a small space for coal and water, but this rig sure wasn't for long hauls. I've seen photos of a number of similar cars, but none were narrow gauge. But you've got a beautiful shot there! Wait, I do remember one n.g. The Grafton Centre RR had a car much like this. The 3' GCRR became the Grafton & Upton RR Regards...