Nield - birth in Bazil

I have a family that were very english, but the father was involved with driving trains. At one stage he was working in Bazil as well as Spain, France and England. I know this because one of his children was born in Rio De Janeiro. I am looking to find out what I do to get birth certificates and if there is any place online or not, where I am likely to find information about the early days of Rail/Trains in Brazil.
Cheers
Allyson
Canberra, Australia