National Rail
http://www.nationalrail.co.uk/

traveline Public Transport Information
http://www.traveline.info/

Arriva
http://www.arriva.co.uk/

First Group
http://www.firstgroup.com/

Go-Ahead Group
http://www.go-ahead.com/

National Express
http://www.nationalexpressgroup.com/

Stagecoach
http://www.stagecoachplc.com/

Confederation of Passenger Transport (CPT)
http://www.cpt-uk.org/

Association of Train Operating Companies (ATOC)
http://www.atoc.org/

PLUSBUS
http://www.plusbus.info/