Friday, 12 November 2010

Turnout operation

Well well well, there's life on this blog after all! Sorry for the absence of anything at all on here for the last few months folks, but basically nothing much has happened in that time!

However, I decided I really needed to just get on and do something - anything! I must confess to having a brief moment or two recently when I wondered if I should just jack in the whole P4 malarkey on the basis that it was to blame for my lack of progress, but I soon saw sense and realised that actually it's got nothing to do with the gauge or scale I happen to have chosen and a lot to do with the realities of daily life, coupled with a general tendency to get sidetracked into other things for months on end!

Anyway, the two key areas that have been holding things up for goodness knows how long are: getting the turnouts operational, and getting my first P4-converted loco up and running. Both are less than straightforward, although this has been due in large part to a kind of rabbit-in-the-headlights instinct - it all seems t0o overwhelming so I'll just stand here rooted to the spot and do nothing...!

The best course of action in these situations is to break things down into manageable chunks. So I decided I should start with the turnouts. They're built, and the Masokits tiebars are ready to install, but that's as far as I'd got. 1) I'm concerned that when I try to solder the tiebars to the switch blades I'll end up de-soldering the tiebars themselves and undoing all the hours of work I put in assembling them in the first place! 2) I really don't know how I'm going to operate them.

OK, so the soldering business is just one of those things where I think you have to give it a go and hope for the best, and if the worst does happen then you just have to bite the bullet and backtrack a bit. Living and learning and all that!

But on the operational side of things, some careful thought and planning was needed. I've spent hours in the past reading up on various different solutions for turnout operation, but none of it has ever quite fallen into place for me. What I need is a solution that is simple, low-tech, idiot-proof, and that I can put together using the most basic and readily available 'ingredients' possible.

So, having a day off work, I popped down to B&Q to see what bits and pieces I could collect together. Perhaps this was the wrong way round to be doing things, but, as I say, sometimes you just have to get out there and do something, even if it is in the wrong order! (Actually, I did spend most of yesterday evening reading various posts on the Scalefour Society forum and RMWeb about turnout operation which planted a few new  ideas and revived a few old ones.)

Anyway, to cut a long story short, after a half hour or so browsing the aisles at B&Q, and a few pounds spent on random bits and pieces which may or may not come in useful, and then an hour or so sat with pen and paper musing over various ideas, I have come up with a plan. Well, half a plan anyway!

Here it is!

I'm not expecting you to be able to figure out what it is just by looking at that load of scribbles though, so I'll try to explain roughly what I have come up with so far.

I had already decided that I'd follow the recommendation that comes with the Masokits tiebars and attach 0.5mm wire that will run out under the stock rail. This will terminate in a 90 degree bend and a couple of millimetres of wire locating downwards into the top end of a piece of brass tube projecting through a slot in the baseboard up to surface level. The bit I hadn't figured out before was what the tube would be attached to underneath or how it would be moved! However, the theory at least is that the turnout/tiebar/wire assembly above the baseboard will be a separate unit from whatever is underneath the baseboard (including the vertical tube), hopefully making life a little easier when it comes to assembling everything (and potentially, disassembling it if that should ever be necessary in the future) as they can be dealt with completely seperately.

For better or worse, I had already ruled out electrical point operation, or memory wire, or anything else that relies on purchasing 'specialist' equipment. As cheap and simple and basic as possible, that's what I'm after!#

So, to try and figure out what exactly was necessary.

Well, the first thing is, the tube that projects up through the slot in the baseboard needs to be held absolutely vertical with no possibility of 'wobble'. It needs to be attached securely and firmly to something under the baseboard. As I don't have the necessary tools to work with metal, the obvious answer is a block of wood, with a hole drilled to the exact diameter of the tubing, allowing it to be held firmly and vertically. Then this block needs to be able to slide back and forth under the baseboard in a controlled manner - in some sort of metal or plastic channel attached to the underside of the baseboard in which the wooden block can run. It will also need stoppers/buffers at each end so it can only slide the required 2 or 3mm to throw the switch blades - this will stop any undue stresses being placed on the turnout itself.

Then the sliding block needs attaching to some sort of rod which will allow for manual operation from the front or back of the layout. I bought a coil of galvanised steel garden wire from B&Q along with one of those hollow net curtain wires. The steel wire runs nicely inside the net curtain wire, which can be attached to the underside of the baseboard using cable clips (the sort of thing you use to attach telephone cables to walls). At one end the wire will simply be bent 90 degrees and threaded through the end of the sliding wooden block, and at the other end it will protrude out of the baseboard edge.

This just leaves the question of (a) how to translate a movement of say a couple of centimetres at the baseboard edge to the 2 or 3mm required at the turnout itself and (b) how to 'lock' the whole thing one way or the other.

With regard to (a), by far the simplest solution to me seems to be to form a loop in the wire (without the constraints of the net curtain wire sheath at this point) which would act as a basic kind of spring. The wire is stiff enough that the loop would not diffuse the initial movement entirely, but flexible enough to take up the excess movement, so allowing a 2cm movement at one end to be translated to 2 or 3mm at the other, with the stress being taken up entirely by the loop in the wire - the stoppers/buffers on the sliding block mechanism ensuring that it and the turnout above don't take any unnecessary strain.

With regard to (b), I have yet to come up with a solution, but again - I'm looking for the least complex one!!

Polarity switching will be achieved by means of simple connectors engaging with the wire or sliding block (again, not entirely sure how but as simple and non-technical as possible!).

I know that to the engineers out there this will all sound so ridiculously Heath Robinson-ish (whoever Heath Robinson is) that I'll probably be laughed out of town, but so be it! I'm not an engineer and honestly don't care what the stuff under the baseboard looks like, as long as it works, is reliable, and is quick, easy and cheap to make. If I had to make it out of Lego to achieve those aims I'd have no shame in doing so!!

Anyway, let's see if I can actually have anything to show for all this in a reasonable timescale.... Set your reminders for 2015!!!!

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