My son used to crew on another Aveling and Porter 0-4-0 "Sydenham" whilst it was at Chatham. With no suspension you could feel it approaching before you saw it. As a model, a 5" gauge loco would be about the size of a 1" Minnie so it might not be the most popular loco on a club track due to its extremely low speed. Perhaps one of the narrow gauge versions (with the drive gears outside the wheels) might be a better choice for a model, as it would be faster and have a larger boiler.
The first locomotives were chain driven 0-4-0s as used on the Brill Tramway **LINK**, later gear drive to the rear wheels only was introduced as on "Blue Circle" **LINK** and finally gear drive to both axles as on "Sydenham" **LINK** (The side rods are not coupling rods but instead stabilise the ends of the axles).
Brian