While trying to decide which Fast Tracks PointForm tool to buy to make the split-point derails, I ended up comparing the various Fast Tracks turnout templates from #6 to #12. In the previous post on this topic, I determined that the #8 had the correct divergence for the prototype. But I was still curious how the other sizes compared. What follows is a little technical, and is mainly recorded here for my own future reference. You mileage may vary.
The templates downloaded from https://www.handlaidtrack.com/track-templates-ho-turnouts come in PDF format. To overlay them, I first converted them to a 600 DPI PNG file, with transparent background:
convert -density 600 <template.pdf> <template.png> mogrify -threshold 50% -transparent white <template.png>
Then, they were selectively colorized (#8 red, #10 green, #12 blue):
mogrify -alpha on -channel rgba -fill "rgba(255,0,0,1.0)" -opaque black -define png:format=png32 *8*.png mogrify -alpha on -channel rgba -fill "rgba(0,255,0,1.0)" -opaque black -define png:format=png32 *10*.png mogrify -alpha on -channel rgba -fill "rgba(0,0,255,1.0)" -opaque black -define png:format=png32 *12*.png
For the multi-page templates, this resulted in multiple files. These were then manually combined in Gimp, aligning the alignment targets, cropping out the right-hand turnout, and saving.
Finally, these modified templates were overlaid using the #6 (still black) as the base.
The 25′ mark is between the ties marked 14 and 15, while the 30′ mark is between the ties marked 17 and 18. These were the two measured lengths of the split-point derails in Le Mars. See previous post for details.
Here are the #6 and #8 (red) overlaid:
It is clear that, by the 25′ and 30′ marks, the #6 diverges too much.
Here it is with the #10 (green) added:
Until you get closer to the frog, the #8 and #10 basically overlap.
Finally, with the #12 (blue) added:
The #12 has slightly less divergence by the 25′ and 30′ marks, but the difference is still minor.
The original assessment was correct that the #8 Fast Tracks turnout will be a good representation of the split-point derails in Le Mars. The #10 would also work, but a #8 PointForm tool may be more versatile.