They own all this:
http://en.wikipedia.org/wiki/Arriva_UK_Trains
Arriva Trains Wales
Chiltern Railways
CrossCountry
Grand Central Railway
London Overground Rail Operations Limited (50/50 joint venture with MTR)
Tyne & Wear Metro
LNWR (train maintenance)
Alliance Rail Holdings
http://en.wikipedia.org/wiki/Arriva_UK_Trains
Arriva Trains Wales
Chiltern Railways
CrossCountry
Grand Central Railway
London Overground Rail Operations Limited (50/50 joint venture with MTR)
Tyne & Wear Metro
LNWR (train maintenance)
Alliance Rail Holdings