Make sure that you have -freeintcam in your trainzoptions.txt file.
Run TRS, go to cab view and use the keyboard arrows (which will now allow free adjustments) to find the view that you want. Take a note of the long string of numbers which is displayed on screen.
Close TRS and open the interior asset for edit. Add the number list you noted down as a new item in the 'cameralist' table. If you want this to be the default view add or modify the 'cameradefault' value to match the new index.
Commit the asset and reload TRS.
@andi06
Thanks for that, I'll give it a try.
Rob.