 Perlman joined the Rio Grande in 1936 as engineer-in-charge of maintenance-of-way work; in 1941, he was promoted to become chief engineer.In 1948, Perlman was general manager; from 1952 to 1954, executive vice-president.At the Rio Grande, Perlman enhanced his reputation as an operations expert with reforms that included off-track maintenance machines (today's highway/rail equipment), transitioning the road from labor-intensive steam locomotives to fuel-efficient diesel-electrics and the establishment of a research laboratory for what was then called "test-tube" railroading.