With the hiatus caused by test building of a new MERG DCC Booster and the preparation for Ally Pally out of the way, (thanks everyone for the nice comments on the London Festival of Model Railways thread) I got back to the main matter in hand, finishing the engineers' possession on Empire Basin and getting back to being able to run trains around again.
Having made the fiddleyard move up and down the next step is making it stay in one place. Until I have a way of accurately holding it at a particular level there isn't much point trying to align tracks etc.
My first attempt was much too wimpy, I didn't use thick enough brass rod for the bolt and the bolts holding the lock onto the vertical section were way to small.
Attempt two used three telescopic sections of K&S tube, a section of the aluminium L to hold a servo and four M4 bolts, altogether much better engineered.
The theory goes that I want the servo to be able to push/pull the bolt in and out. The servo claims 6Kg/cm of torque and I should have the pivot at about 1cm from the centre of the servo head. I'm hoping that with the yard effectively counter-balanced that will be enough.
The other problem I had was that the horizontal shelves were slightly sagging at the front. This was making the front of the shelf about 2mm lower than the rear. To be honest I think the plastic 'easi-rec' inserts were of the cheap and cheerful variety and had a bit too much flex in them. I've now fitted some 2" angled mending plates to the sides bolted through the aluminium with M4 bolts. I marked the holes and then drilled through the square section tube to hold the shelves level. Hopefully now they won't go anywhere.
So now I have to make the second proper bolt. It is a bit late for cutting aluminium section in the garage now, particularly as some of my neighbours have got a new baby! I don't think they'd appreciate the noise.