As with all data that you value and which is held on a computer, it is highly advisable to regularly backup your downloaded and self-created Trainz assets. There are many ways in which data can be accidentally or deliberately deleted, corrupted or otherwise lost.
Making an additional copy on the same physical hard disk only guards against a very limited range of risks. Therefore making backups onto removable media such as writable CD's or DVD's is a wise precaution. If re-writable disks are used then it is best to use at least three sets of disks in rotation.
In addition to backing up their installed files, you may also wish to archive or backup the distribution files for downloaded assets. In most cases these will be CDP, EXE, RAR or ZIP files.
Suggestion: Make a ZIP copy of the folder tree you wish to backup and burn that to CD or DVD. This will require less disks, take less time to burn, and the burning process may be more reliable than writing the numerous original files.
The following instructions assume that Trainz has been installed to its default location. If not, adjust the initial part of each path accordingly.
Downloaded assets are held in the subfolders of C:\Program Files\Auran\TRS2004\World\Dispatcher\Downloads
Assets that you have created are held in the subfolders of C:\Program Files\Auran\TRS2004\World\Custom
TRS2006 & TCEdit
Downloaded assets and assets that you have created are both held in the subfolders of C:\Program Files\Auran\TRS2006\local
Any assets that have been left open for editing can be found in C:\Program Files\Auran\TRS2006\editing