チェコスロバキア国鉄
Born in Prague, Gross briefly worked for Czechoslovak State Railways (ČSD) as an engine-driver trainee. After the Velvet Revolution in 1989, he became a member of the Social Democratic party and in 1992 member of the parliament. After studies in law from 1993 to 1999 he obtained an academic title, although under less than normal conditions. His thesis had a mere 33 pages.