As a safety precaution, you may wish to backup assets that you have created and downloaded before removing any of them.
Layouts that you have created yourself can be deleted in Surveyor.
Other assets can be removed by manually deleting their kuid folder in Windows Explorer.
Alternatively, Trainz Objectz can be used to delete unwanted assets.
Deleting an asset does not delete any of its dependencies. With a layout, the dependencies may number in the hundreds. Trainz Objectz includes an option to list and delete orphaned dependencies.
(The following information is kindly supplied by ColPrice2002)
Routes that have been created by you can be deleted in Surveyor.
Also you can delete any asset that is not built-in with CMP.
To delete a layout and its dependencies:
Open CMP, search form "Location = Local" + "Category = Routes" and select the layout to be deleted.
Right-click and select "show dependencies" from the menu. This lists the dependencies in a pop-up window.
Now click the "view in main screen" button, and all of the dependencies are listed. Press CTRL/A (or use the Select All menu option), then "Delete" to actually delete the assets.
Then return to the CMP list of layouts, select the relevant layout and delete that.
You will receive error messages if you try to delete built-in content and these can be ignored.
The only problem is that you may delete a dependency that's used by another route. You won't find out until you look at all the routes you have installed and look for the missing dependency flag (or try to load the route).
One way of reducing the impact is to archive the route and its dependencies (create a new archive for deleted routes). Carry on as before - deleting everything - if you need a deleted asset CMP will pull it from the archive. Once you're happy that the archive isn't needed you can delete it - this saves you re-downloading.