ðɛɹ pɹˈɛzəns pɹɪvˈɛnts ɐ dᵻɹˈeɪld tɹˈeɪn fɹʌm stɹˈaɪkɪŋ ænd dˈæmɪdʒɪŋ bɹˈɪdʒ kəmpˈoʊnənts, ɔːɹ dˈiːvɪˌeɪɾɪŋ fɹʌmðə tɹˈæk ɪnˈʌf tə lˈiːv ðə tɹˈæks ɛntˈaɪɚli ænd ɹˈoʊl ˌoʊvɚ ɔːɹ fˈɔːl.
Their presence prevents a derailed train from striking and damaging bridge components, or deviating from the track enough to leave the tracks entirely and roll over or fall.