At first, install the Arriva.rwp file

then copy the folders Electric and Passenger from

C:\Program Files (x86)\Steam\SteamApps\common\RailWorks\Assets\RSC\ClassME146Pack01\RailVehicles 


to

C:\Program Files (x86)\Steam\SteamApps\common\RailWorks\Assets\RSC\ClassME146Pack01\RailVehicles Arriva


Decline ALL reports to overwrite.



Finally delete the folder Engine at

C:\Program Files (x86)\Steam\SteamApps\common\RailWorks\Assets\RSC\ClassME146Pack01\RailVehicles Arriva\Electric\ME146



To use the Repaint, tick in the Editor RSC -> ClassME146Pack01.

The dosto cabcar is listed as Arriva DABpbzkfa and Arriva DABpbzkfa nd

and the passenger dostos are listed as Arriva DABpza, Arriva DBdpza and Arriva DBpza.



At the end please clear the cache. Main Menu -> Settings -> Tools




Enjoy!