wˌɛn sˌɛktɚɹəzˈeɪʃən wʌz ˌɪntɹədˈuːst ɪnðə nˈaɪntiːnhˈʌndɹɪd ˈeɪɾi z, ðə nˈæʃənəl ɹˈeɪl lˈaɪnz wɜː sˈɜːvd baɪ nˈɛtwɜːk sˈaʊθ ˈiːst ʌntˈɪl ðə pɹˌaɪvəɾəzˈeɪʃən ʌvðə bɹˈɪɾɪʃ ɹˈeɪlweɪz ɪnðə nˈaɪntiːnhˈʌndɹɪd nˈaɪnti z tə ðə kənˈɛks sˈaʊθ sˈɛntɹəl fɹˈæntʃaɪz, ɹᵻplˈeɪst baɪ ðə kˈɜːɹənt ˈɑːpɚɹˌeɪɾɚɹ ɪn tˈuː θˈaʊzənd.
When sectorisation was introduced in the 1980s, the national rail lines were served by Network SouthEast until the privatisation of the British Railways in the 1990s to the Connex South Central franchise, replaced by the current operator in 2000.