Donner Pass - Track Missing

There's a section of track missing in the area of Cascade bridge. Each time the train gets there, it flies thru the air.
I have a backup of Donner Pass on another drive, which works.
What files/folders do I need to copy from the working route to replace the missing track?
As an aside, when I try installing the Donner Pass upgrade - which worked in TS 2015 - I lose all the green scenario checkmarks. This program will never cease to amaze and annoy me.
Thanks,
Robert
I have a backup of Donner Pass on another drive, which works.

What files/folders do I need to copy from the working route to replace the missing track?

As an aside, when I try installing the Donner Pass upgrade - which worked in TS 2015 - I lose all the green scenario checkmarks. This program will never cease to amaze and annoy me.

Thanks,
Robert
