ɪn wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd sˈɛvənti tˈuː, bˈɔːldwɪn wʌz ɐpˈɔɪntᵻd ðə hˈɛd ˈɑːɹkɪtˌɛkt fɚðə bˈɔltɪmˌoːɹ ænd oʊhˈaɪoʊ ɹˈeɪlɹoʊd, ɐ pəzˈɪʃən pɹˈiːviəsli hˈɛld baɪ dʒˈɑːn ɹˈuːdɑːlf nˈɪɹnsiː, hɪz mˈɛntoːɹ.
In 1872, Baldwin was appointed the head architect for the Baltimore and Ohio Railroad, a position previously held by John Rudolph Niernsee, his mentor.