There is no reason to believe that there was anything outwardly unqualified about this guy—he was a college grad and he went the preferred route of working in the railway environment for years before becoming a conductor.
Likewise, there is nothing to suggest that he was given preference in hiring due to being gay.
What is the average age of someone promoted to engineer?
Maybe you meant to say engineer?
From his own LinkedIn page, he went straight from college (BSBA in Business Administration, General) to being a conductor. Four and a half years later, he became an engineer.
-PJ