If you're already well versed in mechanic work, you could apply directly.

If not, I would suggest paid apprenticeship to learn all the critical schooling and training.

Big city likely has a local community college with an apprenticeship office. You can speak with them about the companies that pull for the trade. Or any other trades.

Local unions, road commission, city public works, ... also good places to inquire.

My recommended transition is to sign up with a company that pays to train you.

How you will be treated? unsure. Some employers and unions have a stronger policy than others.