Odds of Hanging On
Once you get in as a conductor, you'll have very little problem staying on as a conductor. This is the kind of job that gets better with age, as your seniority pretty much makes you choo-choo royalty. You'll do less of the physical labor and get to tell a whole lot more of those "back in my day" stories.
Many conductors actually move on to become engineers (source). When you think about it, who's really in charge anyway: the person who says to go, or the person who actually makes it go?