To uninstall bve-train-br-class-323 just follow these instructions.
/ubuntu/yakkety/universe///install/index.html British Rail Class 323 EMU train (for OpenBVE rail simulator) Ubuntu 16.10 universe/games 4.0.1809-0ubuntu3
sudo apt-get remove bve-train-br-class-323
Which will remove just the bve-train-br-class-323 package itself.
sudo apt-get remove --auto-remove bve-train-br-class-323
This will remove the bve-train-br-class-323 package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for bve-train-br-class-323 then this will work.
sudo apt-get purge bve-train-br-class-323
Or similarly, like this bve-train-br-class-323
sudo apt-get purge --auto-remove bve-train-br-class-323
|Maintainer||Ubuntu MOTU Developers
|Description||British Rail Class 323 EMU train (for OpenBVE rail simulator)|