The process for getting a patron saint today

For some time now I have been trying to get a patron saint for railroad workers, but I have had little success with various dioceses. I think my next step should be getting co-signatures, but how many do I need? World-wide, or would USA suffice? Hard copy? Phone numbers? Addresses? When the signatures have been gathered, where exactly at the Vatican should I send the letter of intent to? Should it be addressed to the Congregation for the Causes of Saints?