Great news! The first of Stefco's dioramas is back in business and here's the proof.
Himself managed to get to the bottom of the mystery about what was preventing the lorry from reversing and completing the full sequence.
A tiny micro switch case had come apart causing it to switch the reversing action off.
So as you can see once the lorry has received the required number of buckets of sand from the excavator it sets off....
Reverses towards a chute where the back of the lorry rises and tips the sand out...
And it returns to its starting position and the excavator begins to dig out sand again.
You may be wondering what happens to the sand once it is tipped down the chute?
It falls down to where an archimedean screw spits it back out at the bottom of the quarry where the bucket is digging.
Very clever, eh?
There is one wee bit that Himself has not been able to restore yet.
There is a lazy solenoid which is supposed to lock the lorry turning arm into place but it will only work if you crank up the voltage, and that would cause everything on the diorama to speed up.
As it seems to work find without the locking mechanism Himself has disconnected it for now.