ɐ mˈɛmbɚɹ əvə hˈɛɹɪɾɪdʒ ɹˈeɪlweɪ, ɔːɹ ɐ nˈʌmbɚɹ ʌv hˈɛɹɪɾɪdʒ ɹˈeɪlweɪz, hˌuː ˈoʊnli vˌɑːləntˈɪɹz ˌɔn dˈeɪz wˌɛɹ ˈɛndʒɪnz ɑːɹ ɪn stˈiːm.
A member of a heritage railway, or a number of heritage railways, who only volunteers on days where engines are in steam.