First you have to be drug free. I wouldn't want them working with my husband and putting him at risk.
Next they have to be willing to work no matter what. It is a 24/7 job. Most people love what they do. If they can get on to a RR and have worked there for a while then they can think about becoming an engineer. It isn't a job you can walk in off the street and do. If the RR thinks you are material for an engineers job they will send you to school.

If they have made bad choices then they need to start at the bottom and maybe work two jobs so they can clean up their act. They also need an education and they need to know how to read. But they also need a good work ethic.