Starting a career as a heavy equipment operator

Hi! I'm interested in starting a career as an operator. Some background: I'm in my mid twenties, worked as a laborer for a few years before going to college. I am a welder right now working part time. I'd like to become a heavy equipment operator though, and I'd like to get into it now so I can start learning the trade while I'm still young and don't have a family to support. I live in the New York City/LI area, and I find that the unions around here are not taking apprentices. So, what I'm here to ask is, for those of you familiar with the trade, business and how things work in NYC/LI, what is the best way for me to get a job or an apprenticeship and learn how to operate heavy equipment?