It is hard to understand your reply. Because i'm not very good with English 
. But as i understand it, i did some changes. Instead of using prefab splines, I created a GameObject named Splines and put the splines in it. Then i assigned them to curvySpline which is in trigger script. And it is working on mobile now. Thank you for your help. Here is my final solution:
. But as i understand it, i did some changes. Instead of using prefab splines, I created a GameObject named Splines and put the splines in it. Then i assigned them to curvySpline which is in trigger script. And it is working on mobile now. Thank you for your help. Here is my final solution: