The Northern suburbs include a large area of Melbourne. Melbourne International Airport is located here in Tullamarine, so the suburbs will be the gateway into Melbourne for many.
There are three train lines that run through the Northern suburbs
The Craigieburn line, which runs from Flinders St. to Craigieburn, It stops in suburbs such as Moonee Ponds, Essendon, Glenroy and Broadmeadows. It is Zone 1 to Strathmore, 1/2 overlap between Pascoe Vale to Glenroy and Zone 2 between Jacana to Craigieburn.
The Upfield line, which runs from Flinders St. to Upfield. It stops in suburbs like Brunswick, Coburg and Fawkner. It is Zone 1 to Coburg, 1/2 overlap between Batman and Fawkner and Zone 2 for the last two stations, Gowrie and Upfield.
The South Morang line, which runs from Flinders St. to South Morang. It stops in suburbs like Northcote, Thornbury, Preston and Epping. It is Zone 1 to Bell, 1/2 overlap between Preston and Reservoir and Zone 2 between Ruthven to South Morang.
Some suburbs in the north have a notorious reputation for crime. You should be careful of your belongings, and avoid travel during the night. There should be no issues during the day. You should exert the most caution in the suburb of Broadmeadows, and around train stations.