Kind of the opposite:

Ned Breathitt was Governor of Kentucky from 1963-1967, and became special counsel to the Southern Railway for Kentucky after he left office. He stayed with Southern and Norfolk Southern until he retired in 1992. He even became Vice President of Public Affairs. I met him around 2000 or so at an event at my school. We had an interesting discussion about his work in the Southern law department.

John W Snow started with Chessie in 1977, rose to CEO, became US Sec. of Treasury in 2003.

Edwin L. Drake ("Col. Drake") was a laid-off railroad conductor in 1857 (New Haven) but got the job of drilling for oil, as local legend has it, because his conductors pass was still valid and he could still travel from New Haven CT to Titusville PA for free - he had no knowledge of oil drilling. "The oil company chose the retired railway man partly because he had free use of the rail. Drake had no military experience, but Townsend gave him the title of "Colonel" in order to impress the local townspeople."

Got to thinking about a shirt tail ancestor who an a grocery store in Sacramento until he teamed up with the guys who ran the hardware down the block and built the Central Pacific.

Walter Davidson (later co-founder of Harley-Davidson) was a railroad machinist prior to his involvement in motorcycles.

Wallace Beery movie actor was a hostler on the Santa Fe!