Please find attached a potential solutions. It isn't the easiest graph to understand because it involves some conditional statements to determine the first and last segment is a spline section, as well as adjusting padding values automatically. It may need some editing for your particular style. Here's a brief explanation..
I've split the geometry into these segments -
Here's how they look in the final style -
The graph itself uses 3 generators as follows. Generator 1
is the most complex and creates the panels. There are 2 conditional operators, one to identify the segment at the start of a spline section, and another to detect the segment at the end. Both use Position on Section
and a percentage to determine whether the condition is true or false. For the end section the percentage is calculated automatically using an equation that returns the segment size as a percentage of the spline section length: return 100-(((1.5*Input1)/XSectionLength)*100);
This file was created in RailClone 3 For RailClone 2 this would be:
Apart from the the rest of the nodes are just adjusting the padding to ensure the pattern fits together correctly. This could be done by hard coding values but here I've tried where possible to use the geometries attributes, which accounts for all the extra nodes Generator 2
adds the mid rail. It's pretty straightforward,the only thing to note here is the use of a Null segment in the Evenly, Start and End inputs that create a gap for the posts which are actually added by Generator 1
add the handrail on top. This one is also pretty straightforward, just a handrail in the top input. All segments have had their Z Alignment set to Pivot so that they sit correctly in relation to the base spline.
Here's a little video of it working: http://d.pr/v/Ztslo
I hope that helps, please let me know if you have any further questions.