Following his graduation from architecture school, Pfaff started working as a professional architect, creating smaller-scale structures such as the 1886 completion of the
Roman Catholic church in
Svábhegy. His work quickly caught the interest of the Hungarian State Railways (MÁV), and he was appointed head architect of the railway business in 1887, a role in which he served for over two decades. The rapid expansion and modernization of railway infrastructure throughout the Austro-Hungarian Empire occurred during Pfaff's time at MÁV. He was in charge of the design, adaption, and renovation of over twenty major station buildings as well as many smaller
regional and
suburban stations across Hungary and the larger imperial regions in his capacity as chief architect and later director of building works. His
design philosophy was in line with the dominant
eclectic tradition, particularly the use of regional Hungarian
vernacular elements in conjunction with
Renaissance revival motifs. Pfaff placed a strong emphasis on keeping balanced proportions and tasteful decoration while emphasizing logical spatial arrangement for passenger movement and operating efficiency. Throughout the MÁV network, this equilibrium made sure that stations were both operational and
aesthetically consistent. Pfaff oversaw repair and enlargement work in
Győr,
Košice (Kassa),
Debrecen, and other regional centers, updating older station structures to accommodate
telegraph installations, greater
traffic, and changing train stock sizes. His work helped create a unifying MÁV architectural character that blended local contexts with imperial requirements. Pfaff's MÁV career established him as an architect who shaped Hungary's railway heritage without excessive ornamentation, resulting in station buildings that are still in use or preserved as heritage landmarks. He also participated in
urban planning consultations for railway-linked developments and contributed to
industrial architecture exhibitions. ==Railway stations==