Unusual PW configurations thread both real and model.

[Pacific231G]

On 10/07/2021 at 01:53, AndyID said:

 

Here's a five way. Looks like a four way would work without any crossings.

 

It might well be. I think the one I saw had a fairly small diameter so it would be interesting to plot the minimum diameter that would enable it to be done with sensible track radii and no crossings at all. Obviously, since the objective would be to save length, you wouldn't want the turntable to be too large. It should be possible to have a five way with one straight track (for the centre road) and just two to one side of it with different radii. Turning it through 180 degrees + or - would allow the two curved tracks to connect the two upper and lower roads in turn. The other thing this would allow, if it was at least the length of a loco, would be to add a loco to the front of a train leaving the fiddle yard and you could have stabling siding for that that did not connect with the running line so using the turntable as a turntable. It would of course requre very precise alignment and workmanship to make such a device work reliably (so I won't be building anything like this!)

[Northroader]

I did make one some time ago. It was something like three roads on both sides coming together, and I wanted to shorten the overall length of the points needed to set up the necessary routes. I had the turntable with a straight line across and two varied curves set back to back at right angles to the straight bit. Where they all crossed, there was a piece of copperclad, with the rails soldered down to the surface, and insulating grooves filed into the surface. It worked after a fashion, but the chief requirement was a really good pivot with no play in it, and it was a game getting all the runoffs lining up once you turned the table 180 degrees.

[AndyID]

10 hours ago, Pacific231G said:

It should be possible to have a five way with one straight track (for the centre road) and just two to one side of it with different radii.

 

Alas! I tried that but it disnae* work unless the diverging angles are very large and the radii are very small.

 

*pH will get it

 

 

 

Edited July 11, 2021 by AndyID
typo, yet again!

[AndyID]

7 hours ago, Northroader said:

I did make one some time ago. It was something like three roads on both sides coming together, and I wanted to shorten the overall length of the points needed to set up the necessary routes. I had the turntable with a straight line across and two varied curves set back to back at right angles to the straight bit. Where they all crossed, there was a piece of copperclad, with the rails soldered down to the surface, and insulating grooves filed into the surface. It worked after a fashion, but the chief requirement was a really good pivot with no play in it, and it was a game getting all the runoffs lining up once you turned the table 180 degrees.

 

I did something similar with a very crude servo controlled sector plate. (I think I posted about it on the old forum.) The track was flexible with variable length rails. It actually worked very well but the interesting thing was I subsequently discovered it really didn't save any length compared with a fan of turnouts, but it was a fun to watch in operation