High Quality Content by WIKIPEDIA articles! Overground Network (abbreviated on or ON) was a branding initiative launched in 2003 by the Strategic Rail Authority and Transport for London, the public transport authority in London, UK. Its aim was to encourage use of National Rail services in South London. The project was a partnership between the Strategic Rail Authority (SRA), Transport for London (TfL), three train operating companies (Connex South Eastern, South Central Trains and South West Trains), the South and West London Transport Conference (SWELTRAC) and the South East London Transport Strategy (SELTRANS).