Passage: Holonyak's father worked in a coal mine. Holonyak was the first member of his family to receive any type of formal schooling.  He once worked 30 straight hours on the Illinois Central Railroad before realizing that a life of hard labor was not what he wanted and he'd prefer to go to school instead.  According to Knight Ridder, "The cheap and reliable semiconductor lasers critical to DVD players, bar code readers and scores of other devices owe their existence in some small way to the demanding workload thrust upon Downstate railroad crews decades ago."Holonyak earned his bachelor's (1950), master's (1951), and doctoral (1954) degrees in electrical engineering from the University of Illinois at Urbana-Champaign. Holonyak was John Bardeen's first Ph.D. student there; Bardeen, a theoretical physicist, was the co-inventor of the transistor who ultimately won Nobel Prizes for that work and for the theory of superconductivity. In 1954 he went to Bell Telephone Laboratories, where he worked on silicon-based electronic devices. From 1955–1957 Holonyak served with the U.S. Army Signal Corps. From 1957–1963 he was a scientist at the General Electric Company's Advanced Semiconductor Laboratory in Syracuse, New York. In 1963, he became a professor at the University of Illinois, from which he retired fifty years later in 2013.

Question: Why did he decide not to work on the railroad anymore?
a life of hard labor was not what he wanted