ðɪ ˈoʊnli mˈeɪdʒɚɹ ˈæksɪdənt ðæt əkˈɜːd ɔnðɪ ˌɛnˌɛssˈiː nˈɛtwɜːk wʌzðə kˈaʊdən ɹˈeɪl kɹˈæʃ wˈɛn, ˌɔn fˈɪftiːn ɑːktˈoʊbɚ nˈaɪntiːnhˈʌndɹɪd nˈaɪnti fˈoːɹ, ðə dɹˈaɪvɚɹ əvə klˈæs tˈuːhˈʌndɹɪd fˈaɪv fˈeɪld tə sˈiː ɐ ɹˈɛd sˈɪɡnəl ðɪs wʌz bᵻlˈiːvd tə hɐvbɪn kˈɔːzd baɪ fˈɑːɡ, ænd dɹˈoʊv ðə jˈuːnɪt ˌɔn tʊ ɐ sˈɪŋɡəl tɹˈæk sˈɛkʃən ʌvðɪ ˈʌkfiːld lˈaɪn, wˌɛɹ ɪt kəlˈaɪdᵻd wɪð ɐ tɹˈeɪn tɹˈævəlɪŋ ɪnðɪ ˈɑːpəzˌɪt dᵻɹˈɛkʃən.
The only major accident that occurred on the NSC network was the Cowden rail crash when, on 15 October 1994, the driver of a Class 205 failed to see a red signal (this was believed to have been caused by fog), and drove the unit on to a single track section of the Uckfield line, where it collided with a train travelling in the opposite direction.