OK- really dumb turnout question- Atlas 55

[u18b]

If all goes well, ChessieFan and I will be involved in helping to build a huge museum layout.

We will be using Atlas code 55 flex (hopefully they will have produced more by the 9 mo to year when we are ready to use it.

But turnouts.  Hmmmm.

I am REALLY drawn to the Fast Tracks turnouts.  What I like almost most importantly is that there is no linkage in the point rails.  You have solid contact from almost to the frog all the way to the tips of the point rails.  They just bend slightly like the real thing.  Point Rail linkages are a potential electrical weak spot in a turnout.  In the past. I have spent UNTOLD hours soldering jumper wires i order to create (say) a Peco turnout that would not fail.

Well, someone is encouraging me to use Atlas code 55 (there may be some cost savings involved).   So I'm holding an Atlas #10 in my hand.

Here is my radical crazy idea.   

What would happen if I held the points in the middle position and then gently SOLDERED the point rail joints?   

Would the Atlas turnout function just like a fast tracks turnout at that point?  With the rails now bending.  Would it work, do you think?  What would be the downfall of doing this.  Maybe the point joint breaking and then I have a non-functioning turnout that will have to be totally replaced?

Remember, this is for a museum layout that we hope will exist for 50-100 years (glassed in to keep dust off).  It will have potentially heavy use- much more that if the turnouts were on my home layout.

Please be kind to me if this is a really dumb idea.

Ron Bearden

[MichaelWinicki]

Not a dumb idea at all Ron.

I've done exactly that with a few of the Atlas switches where I've had problems with the point rail not making a good connection with the small brass plate the end of the point rests on.

#5's, #7's and a couple #10's.

It takes less than a minute and I do it with the turnout right in place. 

It's a fast and easy fix.

Some of these switches are thrown every day and have been for the past 4 years– no more issues.

[C855B]

Also with a #10 in my hand right now (...well, maybe not... too hard to type...), this is an intriguing idea.

I agree in impromptu testing that a weakness might be the joinery with the plastic at the throwbar. On the other hand, on closer examination the joints are pretty strong, probably designed to endure the abuse of twin-coil switch machines. You cannot beef it up by making it a solid metal throwbar, at least not without doing a bunch of surgery around the point pivots to disconnect them from the stock rails.

:thoughtful_chin_stroking:

I am still in testing mode with RC servos for switch machines. I have no problem with trying this idea. I'll add it to the project.

[u18b]

Having filed a little on the points to make them sharper, it is clear the points are cast and plated.

So a weakness of my idea might be that -- once soldered, the joint (in essence) is now held fast by the plating.  So one day, the plating may break (not the solder itself).

[GaryHinshaw]

My guess is that the solder joint would fail over the life time you are projecting.  But if you're willing going to the trouble, maybe you could embed a jumper wire in the solder joint so even if the joint breaks between the point and closure rail, the jumper wire would still bridge the gap.

I think Fast Tracks have a similar issue with the point-throwbar joint: there is some modest torsion on the soldered joint because the points are not hinged.  That can become an issue over time, depending on how carefully to make and test your solder joints, and on what kind of actuation you use.

By the way, does anyone have experience with conductive grease, something like this?  It seems like a bit of this dabbed on the joint would be helpful, and not un-prototypical.

-Gary

[MichaelWinicki]

My guess is that the solder joint would fail over the life time you are projecting.  But if you're willing going to the trouble, maybe you could embed a jumper wire in the solder joint so even if the joint breaks between the point and closure rail, the jumper wire would still bridge the gap.

I think Fast Tracks have a similar issue with the point-throwbar joint: there is some modest torsion on the soldered joint because the points are not hinged.  That can become an issue over time, depending on how carefully to make and test your solder joints, and on what kind of actuation you use.

By the way, does anyone have experience with conductive grease, something like this?  It seems like a bit of this dabbed on the joint would be helpful, and not un-prototypical.

-Gary

While I've had Fast Tracks points/throwbar fail on me at the soldered joint, I've yet to have one of the Atlas switches fail where I've soldered the point to the brass plate... Not saying they won't of course but after throwing many of those switches a few thousand times I would expect that if they were going to do that they would have already.

[GaryHinshaw]

While I've had Fast Tracks points/throwbar fail on me at the soldered joint, I've yet to have one of the Atlas switches fail where I've soldered the point to the brass plate... Not saying they won't of course but after throwing many of those switches a few thousand times I would expect that if they were going to do that they would have already.

Thanks Michael.  Good to hear; actual experience is much more valuable than hunches.

[peteski]

By the way, does anyone have experience with conductive grease, something ]http://www.amazon.com/MG-Chemicals-Carbon-Conductive-Grease/dp/B000KQ1CWO]?  It seems like a bit of this dabbed on the joint would be helpful, and not un-prototypical.

-Gary

Gary, the grease with carbon you found has a resistance too high to make a good conductor for conducting the amount of current (with minimal voltage drop) needed by a locomotive engine. Its specs state that it has conductivity of 117 ohm/cm. The testimonials of its wonderful properties are given for applications where it pretty much acts as air and moisture barrier for connections which are static (like automotive connectors).

That is not to say that there aren't conductive greases out there which would actually have resistance low enough to work the way you envisioned it.  For example http://www.2spi.com/catalog/vac/silver-filled-grease-techdata.html  Has conductivity of <0.01 ohm/cm  which would pretty much be similar to a piece of wire.  But because it is silver-based, it is quite expensive.

I don't like the conductive grease solution because it is not a  permanent solution. In most cases, grease needs to be periodically re-applied.

[mmagliaro]

First, let me say that not only is this NOT a dumb question, but now I want to try this myself!
I have been installing turnouts all over my current under-construction layout, and I have been carefully
soldering fine flexible wires, from underneath, embedded in recesses I cut into the underside of the ties,
to bridge that hinge, because I know it will electrically fail sooner or later.  I though that soldering that joint
solid would make the rails too inflexible to move!

I will say this... I have soldered rail joints with no joiner before, and over time, every one of them pulled apart
due to expansion/contraction and flexing of the joint .  Only when I bridged a piece of fine wire across the joint and then
soldered, did it last.  So I would suspect that over time, these soldered hinge joints will break unless there is a piece of
fine wire soldered in there.

.... and I'm going to try this on the next turnout I install.  It sure is a lot less work than soldering those wires from underneath!

[GaryHinshaw]

Thanks for the great info Peteski, I thought you might have some useful knowledge about this.   I'll look into the silver-bearing grease.   I agree that it would occasionally have to be re-applied, but to me that is also one of its potential advantages.  Like Max, I have found it very tedious and somewhat challenging to solder a flexible connection between point and closure rails from underneath, and I'm looking for simpler alternatives.  I have a slightly different situation since I'm hand-laying.  I have three separate conductive paths between the points and the outside world: 1) point to stock rail contact, 2) point to closure rail contact via a nickel silver joiner, and 3) point to PC tie to stock rail contact (the bare copper segments in this shot):



So far I have not had any problems keeping the points powered without a jumper or grease, but my experience is still limited.  A little conductive grease applied to any one of these connections must enhance reliability.  (By the way, the rails & PC ties are blackened not painted, so still conductive.)

-Gary

[MichaelWinicki]

First, let me say that not only is this NOT a dumb question, but now I want to try this myself!
I have been installing turnouts all over my current under-construction layout, and I have been carefully
soldering fine flexible wires, from underneath, embedded in recesses I cut into the underside of the ties,
to bridge that hinge, because I know it will electrically fail sooner or later.  I though that soldering that joint
solid would make the rails too inflexible to move!

I will say this... I have soldered rail joints with no joiner before, and over time, every one of them pulled apart
due to expansion/contraction and flexing of the joint .  Only when I bridged a piece of fine wire across the joint and then
soldered, did it last.  So I would suspect that over time, these soldered hinge joints will break unless there is a piece of
fine wire soldered in there.

.... and I'm going to try this on the next turnout I install.  It sure is a lot less work than soldering those wires from underneath!

Possibly it's more sturdy than say a soldered point between the point and the throwbar is because not only is the small blob of solder connecting the point with the rail going to the frog (area), but it's also soldered to the small brass plate. 

And quite honestly when looking at it, it seems to have less stress there than the point/throwbar area.

[peteski]

You're welcome Gary. 

As far as the flexibility of the points (on a handmade turnouts), has anybody considered the possibility of thinning the rail profile to make the rail more flexible in the spot where commercial turnouts have the pivot point?   All that might be needed is to grind down the base of the rail for about 1/4" to 1/2".  I know that it is not prototypical or pretty solution, but from purely mechanical standpoint it would relive quite a bit of stress at the throwbar.  As for example, this is pretty much how tweezers are constructed. In tweezers there are 2 pieces welded or riveted together to form a V shape. But if you carefully observe how they flex as you close the tips together, the thickness of each blade is ground down to be thinner right before the weld.  That is how the tips can close with very little pressure applied.   I have actually ground that area on some of my stiff tweezers to make them close easier.

[nkalanaga]

How will the turnouts be thrown?  If they use any type of switch machine, they'll have to be maintained.  It wouldn't be hard to attach a SPDT microswitch to the machine and power the closure rails that way.  The point-closure rail joint becomes irrelevant, and the microswitch will probably outlast the switch machine.  If it fails, it can easily be replaced.

[u18b]

Well that didn't go very well.  (Paul Graf gives himself a facepalm)   

I went ahead and tried the soldering.  But the ties overheated and some damage was caused (even though I was using heat sinks).

But worse- the solder does not stick very well to the plating.

Also- the locking washer does not hold solder at all.

The turnout is pretty simple. 
Brass base with a hole (that bass base is under the opposing rail too).
Point rail with a knobby ball at the end- goes through the hole.
A locking washer fits over the ball on the underside.
That's it.

So when you try to heat everything up, the brass base runs through the tie and it heats up and starts to melt the tie.  And solder won't stick at all to the washer.
And you have to keep heating and trying to get solder to stick to the ball and the plate (yes, even with flux).

I did get everything to stick finally.  Points are stuck right in the middle like I wanted.
But the points - with their back portions soldered down- the points rose above the height of the rail.  They probably need filing down (which I started doing.

So I would not call this a success (Cory mutters- That Bearden tinkers too much) 

Mike, how did you get this to work with the problems I encountered.  Did you solder from up top or below?

[peteski]

Ron,
back on the Atlas forum I asked Atlas peeps what they used for the top plating on those turnouts but nobody volunteered any info. 
From my dealings with these it appears that the actual parts (frogs, points and guard rails) are cast from some sort of white metal (maybe Zamak), then they are copper plated then the final plating of a shiny silver metal is applied.  I think that if you carefully ground the top plating off exposing the copper, then soldering would be much easier. As for the round washer/point-retainer, I dont' knwo what it is made of.

I also suspect that the people who say that they successfully soldered in those areas did not truly get the solder to wet the metal surface. They just globbed the solder on and it is held simply by the roughness of the metal surface (not a good solder joint).