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Those Point Switches

Posted by Crosland , 07 August 2014 · 972 views

There are no more dead sections. The power was routed by the frog switches to a lot more track than I thought, but all the dead sections are sorted now.

Confession time. The permanent short was the classic error, that I really should have spotted, of there being no isolating gap between back-to-back points. Or, at least there was, but I didn't spot that it had been linked across. Some clever DC power routing I suspect. The short happened when I added extra feeds for DCC.

The point operation is an interesting mix of wire-in-tube and OO rail held in bent nails :o, sometimes both:

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You can just see the OO rail going top to bottom on the underside of the baseboard. It connects to the wire-in-tube a few inches away, which then returns to the switch.

I am now left with four gaping holes in the scenery :( but at least there's plenty of access to attach servos to the tie bars. All of the switches are make-before-break and cause the command station to shut down. I'm using an EZ-Command for testing. Eventually it will, of course, be a SPROG but I can't be bothered to turn the laptop on every time I want to test something :)

I don't want to disturb the points too much but two switch rails have come adrift from their tie bars, which explains the large gaps commented on in an earlier entry. It's an object lesson in what can go wrong with soldered joins between switch rail and tiebar. The throw of the existing switches is too great, contributing to the larger than finescale gaps. I suspect the alignment was not quite correct, putting pressure on the soldered join when the switch rail was pushed against the stock rail.

Thanks for all the comments!

Andrew
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nick_bastable
Aug 07 2014 20:16

excellent progress well done 

Really enjoying reading of how your tackling the challenge you've set yourself with Arnoldale - and the puns, and just a bit puzzled by the lack of a run around loop. I presume it was originally based on a GWR branch that used rope/horse/gravity shunting.

 

With regard to the point switch toe clearance I tend to favour around 1.0mm to allow a bit of wriggle room - and a bit more if the track point entry isn't dead on square - since 0.62mm is the absolute figure. I also prefer pivoting tie-bar joints as it assists here with both clearance and reducing load on the blade/tie-bar joint - useful if you intend using servos.

 

Izzy

Interesting about the run around loop. It was definitely a GWR flavour layout, or so I believe. I have been thinking that adding a loop would be an excellent excuse to try building some points :)

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Nigelcliffe
Aug 09 2014 17:30

Andrew,  I assume you know that an EZ Command with its supplied Power Supply puts out a very high track voltage.  Enough to cause problems with some small decoders in my experience.   If you want to try something more sensible, around 11v AC supply seems to give a sensible output from an EZ.  ( Or use the EZ to power a lower output booster :)  ).    The EZ also only delivers 28 speed step instructions, so takeoff from standstill may not be quite as smooth as you can achieve with better controllers. 

 

I think the run-round might require some modifications near the buffer end, possibly loosing the road which goes across the buffers to make the line a bit longer to get the cross-over in without being too cramped and spoiling the effect.   

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