Frog switch for copper-clad turnout construction

[AndyID]

This is an old idea that I've used successfully for years. It's pretty cheap-and-cheerful but despite that it's very reliable. Hopefully the pix and diagram will explain better than me waffling on about it.

 

 

 

 

And here's a diagram that might explain it a bit better.

 

 

It's basically a sliding contact switch. There is a phosphor-bronze strip soldered to the tiebar (stretcher). It has two dents that form point contacts with the copper laminate timbers. The phosphor-bronze strip is preformed slightly to maintain a little pressure between it and the timbers. The only slightly tricky bit is cutting the two isolation breaks in the timber (to the right of the tiebar in the diagram) so that there is a "dead' section as the tiebar moves. Without that there will be a short circuit.

 

If you don't like the PB strip on the top of the timbers it would not be too difficult to hide it on the underside, although I've never bothered.

 

BTW, the sliding action of the switch makes it extremely reliable and it's impossible for the frog to be at the wrong polarity for the points setting.

[ikcdab]

this is an excellent idea, really simple and effective. Even better if the switch could be hidden under a facing point lock cover.

Ive used microswitches, wished i'd seen this before.

[Gordon A]

I prefer micro switches with levers to change the polarity of crossing V's. They have the advantage of being in their own case keeping the contacts clean.

 

Gordon A

[Michael Edge]

I used this idea more than 40 years ago with my first exhibition layout, it worked quite reliably, using phosphor bronze strip on the pcb sleepers. It did tend to get dirty after a while, usually cured with electrolube but if I was using it now I would apply graphite to the sleeper. I have a similar setup for the hand powered turntable in my latest fiddle yard, this wasn't very reliable until I added graphite to it, now it's almost 100%.

[RedgateModels]

I'm DCC and have just done my first manual SMD PCB for a project being developed by a MERG member ...

 

 

I suppose I'd better test it 🤪

Edited July 12, 2022 by RedgateModels