ˌɔn ʃˈɑːɹp kˈɜːvz, ɡˈɑːɹd ɹˈeɪlz mˈeɪ biː plˈeɪst ɪnsˈaɪd ðɪ ˈɪnɚ ɹˈeɪl, wˌɛɹ ðeɪ ɛŋɡˈeɪdʒ ðə bˈæk ʌvðə flˈændʒ ʌvðə wˈiːl ˌɔn ðæt sˈaɪd.
On sharp curves, guard rails may be placed inside the inner rail, where they engage the back of the flange of the wheel on that side.