I have had this problem although I don't know what caused it. But I was able to fix it. Zoom way out, then for each baseboard with the problem, use the Surveyor Classic topology/plateau tool, set the radius to fairly small, then slightly modify the terrain.
Until.....perhaps...... N3V partners with the developers of junxions https://junxions.com/ which could result in an add-on pack to Trainz, or an entirely new game. Unlikely but fun to fantasize about.
I have Trainz Plus build 126280 with the same problems on my large routes. In Surveyor, it seems to be the result of moving around the route a lot vs working in a small area. Never had this problem in older versions of Trainz.
Increasing my PCs RAM from 16 to 32gb did not entirely solve the...
And some of these proposed rail lines in Bali will be subways!
https://www.abc.net.au/news/2024-09-04/bali-subway-project-tourist-rail-by-2027-traffic/104235836
I have the same problem with splines (both track and roads) on a large route I had been working on. I have posted on this problem in the past.
I tried deleting vacant baseboards and then save/exit the route/reload the now much smaller route. No luck. That route is corrupted apparently.
But...
For some reason, probably lost to time, the non-default settings of YARNish intersections (streetlights, signals, etc) are stored on the session layer of a route. This didn't cause a problem since there was no simple way to copy an entire village or town from one route to another. With...
I'm sorry this did not work for you.
The route I copied terrain from was my own, so certainly not payware.
I hope someone from N3V will see this and comment on whether the prevention of pasting terrain only from a payware route was intentional or an oversight that could be corrected...
Since you have Surveyor 2.0, here is a suggestion which I have done myself:
Find a route, either on the DLS, or one of the built-in routes that came with Trainz, that has suitable terrain that you want to use in your route. Load that route.
In Surveyor 2.0, select an area and copy it. It...
I agree that many hours of work would be needed.
You could argue that the TransDEM user could just create a route for the requestor consisting of a huge chunk of terrain, then email the .cdp file and let the requestor delete what they don't want. Of course, this would result in a route too...
Another use of the copy/paste tool in Surveyor Classic. Find an area with nothing on it Copy and then deselect paste height and paste textures. Now paste over an area of objects and splines to delete them. This is a quick way to clear an area you no longer want existing objects and splines.
This sounds similar to problems I and others are having.
https://forums.auran.com/threads/my-latest-logs-sent-in.179069/post-2030823
Scroll down to my post to see why I think it's a memory cache problem, although others may disagree.
You didn't mention what version of Trainz you are using...