Federation happened in 1901, but it wasn't until the 1890s that most of the colonies started to warm to the idea of being a united nation.
Some 'obstacles' of federation was the fact that South Australia didn't want to join because that was the only convict free colony and they didn't want to mix In with convicts that got transported over from England. They believed that there would be a huge rise in robbery and other punishable offences so it wasn't until later on within the 1890's that they started to push in the favour of federation.
There was also a huge overwhelming fear that some of the poorer and undeveloped colonies would be left out and forgotten by the rest of Australia, due to the fact that some colonies only grew vegetables which would then be transported to the other colonies at a small fee. Since agriculture was being some colony's backbone they would have a hard time fitting in to a country that thinks of them as the lower class citizens.
I believe that one of the biggest fears of the governors of each colony was that they would entrust all their money to one man that might play favourites to a particular colony or state such as having better funding for schools in NSW and leaving colonies such as W.A out of the picture frame. So instead of a colony getting rich and buying better schools, buildings and maintenance for their own cities the prime minister would take virtually large amounts of money from all d colonies and might perhaps only spend money on improving their best cities rather than caring undeveloped cities.
Some benefits of federation was that Australia would have a much greater navy, army and air force due to the fact that they would...