Large Scale Central

3D Printed No 4 Switch

Not sure this would be useful outdoors due to thermal expansion and contraction but:

I thought it would be a fun exercise. I printed it in three pieces due to its size, but can print it in just two parts. The rail is code 332 just because that is what I had handy to measure. I think the frog and the corresponding stock and diverging rails that are part of the piece on the right may be of some use outside if printed with the right material and some allowance is made for movement.

Let me know what you think.

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How does it work with your stock?
It would be good for storage tracks…

Sean, unfortunately I have not had the time to add track and roll anything through it other than the trucks you see in the photo. I took it off the printer at 2:30 AM on Christmas morning as we were literally walking out the door on a trip to NC. I’ll set up a short test track when I get back and see how longer rolling stock and an engine rolls through it. The set of trucks I did roll through it had no issues free rolling through both directions.

Cool Project. I was thinking of doing something very similar for when I do the ceiling layout. Why? Just to see if I can. It will all be a single run (no turn outs) and I was originally going to had lay it. But then I thought it would be a fun experiment to see if I can resin print it when I get my larger printer.

David Leech (MLS) has done some research on 3D printed coach sides and how they survive outdoors. I guess it depends on the material you print it from?

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I have no info on filament printing. But with resin, since it is a UV cured product and over curing causes stuff to become very brittle, I guess resin prints used outdoors tend to get brittle overtime. I would assume painting would stop this by blocking out the UV. But that is not to say that other elements don’t effect it either. But I have been told by others to make sure I paint all my prints to prevent further curing.

Devon, I started this project just to produce the various size frogs to use since I think that will work and the frogs are the most difficult and critical part of the switch. I think with some thought and correct use of materials, the thermal issues can be overcome. We will find out soon.

Pete, the material selection will certainly impact the thermal movement so it will be important to choose the correct one. My intent would be to only use the frog section.

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Dan I posed a similar question because this build has given me inspiration to build the one lone turn out I need for my indoor. It has to be a very tight radius turnout I think a copy of the LGB R1 will work. And yes it needs to be as “curved” as possible. I realize that prototypical turnouts have a certain amount of “straight” to them and I understand the physics of why. But I will need mine to diverge as quickly as I can into a 30" diameter radius curve. So the straight shot through the turnout needs to be minimal if not an outright curved frog.

So my question to you is how are you going about setting up the geometry so that I might be able to copy the process. Right now my plan of approach is to design the rails (Llagas code 215 Nickle Silver) and lay them in there and virtually start constructing the frog at the intersection. Is this the right approach?

Could you make a curved switch?
Like on this site :

So as to not hijack Dan’s thread, I started a new one. So we can discuss my project there. But to answer question I could but that is not what I really need. I will explain in better detail in my thread.

I don’t know about ‘virtually’ as you probably need a ‘real’ frog, but that’s the way I always did it - but for larger diameter I used a drawing. (I have both PRR and D&RGW prototype drawings.) This is a D&RGW of a #4.5 switch:

It is easier to make a full-size drawing and then curve the rails to fit.

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