Dude, go for it. If you hire out now and like it you are set for life. These guys are right that it can be hard sometimes. The RR is feast of famine. I have not seen it first hand but have heard the stories from the older guys. The upsides are the rail industry is doing nothing but growing right now. The price of gas is helping and gas is probably never gonna go back down so it will probably contine to grow for years. Plus, the RR can't be shipped overseas to have cheap labor, gotta pay us here to do it. The pay is great in my opinion, at 18 you will probably make more money than you ever have, after you mark up. The work is not hard, just taking them outta one track and putting them in another. The benifits on the RR are second to none. The retirement is much better than anything social security will ever give you if it is even around when you are retirement age. At your age you can put in 40 to 50 years and retire and you will probably never have to worry financially about anything, plus your spouse will get a retirement from the RR as well w/o ever working a day. The spouse draws 48% of whatever RR retirement that you draw, so if you draw 4000 she/he will draw 1920 dollars on top of that making you together bringing home 5920 dollars retired. For a job that requires no more than a HS education you cant beat that. Those figures are off the top of my head, the amount you draw depends on how long you work (# of yrs) and your highest paying years, so it could be less or it could be more.
You will probably go through a time every now and then where you don't make much, but that will happen when you are low seniorty, the longer you are with the RR the easier it is to depend on the paycheck because the more seniorty you have the easier it is to get the jobs that you want.
Over all is is a really good job. I wish I had hired out at 18, I would be in the dependable period by now.
Go for it, you can always quit if you don't like it.