Monday, January 19, 2009

NSWGR Handlaid Trackwork- pt3 construction

I think that I should expand on just how I activate my points. It's really cheap and simple, and easy. It all revolves around a DPDT switch. I only use three contacts on the switch, the others I leave 'just in case' I need to use some switching down the track.

I put a hole in a piece of timber that is big enough for the switch to go through, then I put a hole in a second piece of timber large enough so that it doesn't bind on the nut of the switch. The two pieces of timber need to fit flush against each other. This is one side of the box, the other three should be made to go around a single piece of timber that will activate the switch. I built all of this with some scrap 3mm ply and some pine about 25x7mm, using three pieces of the pine and three pieces of the ply. The pine is solid enough to drill a hole into the short side , so that the end of the switch fits snuggly into it. The switch itself performs two roles, to change the polarity of the frog, and to mechanically move the point blades. The piece of timber that fits in the centre of the box i sand a bit on the corners so that it doesn't bind, before putting it together. As you can see from the photo I install the box on its side so that its easy to solder on the wires (easier still to do it before you put it in place). Talking about the wiring I make the centre pole for the power to the frog, the LHS pole goes to the right hand track, and the RHS pole goes to the left hand track. Really what I'm saying is that the polarity is reversed so that everything works when you 'switch' the point. If this doesn't make sense let me know and I'll try to explain it more

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