Hi, did you ever get a solution for this ? I have the same problem and don't know how to get rid of these white lines.
Rail4Pete
Sadly no, N3V does not appear to want to implement this simple fix I linked in my previous post and rather wants us to spend ridiculous amouts of time to re-lay all the "Missing Spline" track or hunt down missing track assets all across the internet.
It's been 2 years since I suggested the (minimalistic and super-easy) fix and still nothing happened, not even a response from N3V, so I suggest you better not wait for it.
There were multiple opportunities for N3V to fix it in one of the many updates which were released in the meantime though.
Luckily I was able to import the track assets I used from a very old backup, then had to fix the gazillion of content errors and could then finally replace the old track with new one.
If you just want to get rid of these missing spline assets you can click on the menu in the upper left in surveyor and select to delete all missing assets from the route, but be aware that it does what it says and you can not get it back for replacement later and it affects all missing assets, not just the track splines.
I recomment you to create a backup of your Route first before you do this, just to be safe, that way you can restore it if it did not have the wanted effect.
Tata
Mr.Jingles
