This is a glass-topped table. The glass is 18" in diameter. The top is divided into four sections, each modeled to be a display in a zoo, for polar bears, giraffes, tigers and deer. These correspond also to the seasons of the year, Winter, Spring, Summer and Fall. There is a Z-scale train that carries visitors around the exhibits. The image at left shows the whole table (before the animals arrived). Below is a Thomasson Film of the table:
Here is a closer view of the zoo with animals. There are two polar bears, three tigers, three giraffes, and four deer. The animals are at a scale of 160:1 (N), the train at 220:1 (Z), simulating the zoo train being at a reduced scale, and allowing access to the wider range of accessories available in N-scale.
View from directly above. Can you find all the animals? One tiger is hiding on the grass underneath the tree in their enclosure.
This is an "open plan" zoo. One deer has strayed across the tracks. However, the tigers are contained by a wall and a moat, for the safety of visitors and the conservation of rail crew. Visitors are encouraged to view the animals from open flat cars: You can see below some visitors enjoying the deer enclosure from the flat-topped wagon pulled by the zoo's steam locomotive.
Here are pictures showing the detail of each enclosure.
The deer are presented in Fall; rich trees with autumnal colours are combined with stone tunnel portals and panoramic forest backdrops to give a dazzling natural feel. The track is being checked from a small railcar in this picture.
The polar bears in this zoo are actually rather tame, or possibly just lazy. (They are apparently related to some bears who made some well-known TV commercials a few years ago.) One is enjoying the excellent pool with which their winter scene is equipped. It never gets cold enough to actually freeze here, and the icy aspect is a fake as you may be able to tell from the strip of grass beside the track, but it makes the bears feel at home. The tunnel portals have been made with white limestone, quarried of course by certified Eskimo stonemasons.
If you have paid attention to giraffe enclosures on your visits to other zoos, you will have been struck by their denuded state. We maintain a spring aspect to our small slice of serengeti by having a synthetic tree to which we attach foliage for the giraffe to pick off, and by carefully spreading a proprietary mix of giraffe, bear, deer and tiger poo over the manicured lawn of foul-tasting crab grass.
Our tigers also have a lawn. Their moat is stocked with their favourite fish, as well. They have to have a wall and moat in case the deer or giraffes (who like to peer in and tease the tigers about being short) wander through the tunnels, or the train drivers are not on their toes.
Here is a picture of a 3-foot-tall person (Edwin) playing with the layout, and some zoo patrons looking at the polar bears.
You may be able to make out the aluminium box containing the
controller; it is mounted between the feet of the table,
underneath a platform of wood.
The control electronics is a new design by your humble author. It is a feedback regulator type, so that it adjusts pulsewidth to regulate the engine back EMF, sensed during the off part of the cycle. It differs from previous controllers of the same type (such as the Gaugemaster) in that it will work with either rectified DC, AC, or fully filtered dc such as from a battery. Battery capability is unusual for a feedback controller. The design contains no electrolytic capacitors so it does not filter supply that is unfiltered. In addition, it has an inertia option. I believe being a feedback controller with inertia makes it unique. It uses only one dual opamp IC and a pass transistor, in addition to R, C and diodes.
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