Thanks for clarifying. Please find attached another approach. Because RailClone use a grid like array, it is necessary to slice your segment so that it can be used in a grid that will be sequentially offset.
I've cut it like this, the important thing here is that both the top and mid section are an identical height.
Once that has done we need to create the pattern. To do this I have used the Selector operator and an arithmetic expression that uses the modulo function. This is ideal for creating repeating counters that are perhaps more complex that the built-in sequence operators allow. The expression I used was if(mod(SegmentXCounter-SegmentYCounter,Input1)+1=1,1,2)
Input 1 represents the number of segments over which you'd like the pattern to repeat on the X and Y axis. As you can see this expression is taking into consideration the segment count on the X and Y axis.
Apart from that the rest of the style is pretty straightforward. I've added Start End and Evenly in case they are needed and used a separate generator for this for greater flexibility.
I hope that helps, please let me know if you have any further questions.