The hours can be brutal. My shop's managers worked a salaried 55+ hour work week, half of us were the night shift managers w/ 12-13 hour shifts. This means you'll be lucky to have 1 rest-day that falls on a 'normal' weekend (Fri, Sat, Sun).
At my shop, if you took a vacation day, that usually meant that another manager had to come in off their rest day to cover your shift. In the case that an older manager takes a week off, you may be working 7-9 consecutive days.
As much as my management raved about the annual salary, I only saw ~61% of my paycheck (assuming no 401k contribution), which is the the downside of railroad retirement :(
If working as a non-Omaha manager, prepare to relocate to a random location every 1-2 years (if you perform your job really well or are hated by your coworkers at your current location).
IF you were hired as a manager right after graduating college, you will be resented and disliked by quite a few union workers. By all means, this isn't a deal breaker, but you'll have to learn how to improve union relations right off the bat. It was interesting to see the management vs. union struggles during my time with Union Pacific.