Faller Circus World Roundabout 140331 - Construction Log

It's hard to see in the image above, but under the hill there's a drive shaft that is connected to a long spring that runs the length of the track back round to the hill.
This will drive the vehicles around the track.

The heat sink on the right-hand circuit board gets very, very hot.
The left-hand circuit board causes the clown above the cash box to illuminate.

Testing Phase
I was unhappy with the way the model worked, as constructed. There were a number of problems that needed to be addressed:

Problem: The lead car would stop on the last corner before the hill.
Cause: This was due to the 'pins' on the lead car loosing contact with the drive spring. The track is screwed down (from below), but there is no screw at that particular corner and the track was not resting on the base at that point.
Solution: The instructions state that the track shouldn't be glued down. I decided to ignore this advice and removed all the screws and glued the track down instead. This fixed the problem.

Problem: The lead car would get stuck on the right hand side of the hill.
Cause: The drive spring runs from the bottom of the hill, around the track, back up the hill and partially down the other side. Therefore there is a small gap on the down-side of the hill where there is no spring. On my finished model, this gap was too large to allow the drive pins to transition over the gap.
Solution: After removing the spring, I carefully pulled on the tightly wound section that is connected to the drive shaft. This spread out the coils slightly and extended the overall length of the spring by a few millimetres. After reinserting the spring back into the track, the gap was now sufficiently small enough to allow the lead car to transition this gap successfully.

Problem: The lead car pulls the other cars around the track. The trailing cars kept coming off the track.
Cause 1: The cars are very, very light. The slightest jolt and they jump off the track.
Solution 1: I glued a small magnet to the base of each car in attempt to pull them down towards the spring. This solution was only partially successful, although it did add weight to the cars. There was an extra wheel & tyre left over in the box so I glued this onto the back one of the cars as a "spare", and for additional weight.
Cause 2: The 'pin' used to keep the trailing cars following the course of the track is too short.
Solution 2: I glued an additional, longer pin to the base of these cars. See photo below.

I was now much happier with the way the model functioned, although it's far from perfect. The only slight problem is that the motion of the cars is a little jerkier on the left-hand-side of the model than the right-hand-side. I think this is due to the number of bends in the track - each bend adding more resistance to the turning of the spring as it gets further and further away from the drive shaft.
Anyway, here's the finished model:


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