The Main North Line (also known as the Great Northern Railway) is a major railway in NSW, Australia.  It runs through the Central Coast, Hunter and New England regions.  The line was the original main line between Sydney and Brisbane, however this required a change of gauge at Wallangarra.  As of 1988, the line saw rail services progressively withdrawn north of Armidale with services gradually withdrawn till 2005.  The line starts as a branch off the Main Suburban line at Strathfield in Sydney.  The line heads north as a quadruple track electrified line to Rhodes, crossing the John Whitton Bridge over the Parramatta River as a double track line.  At West Ryde the line again expands out to four tracks through to Epping.  The line is then largely double track through the northern suburbs of Sydney, crossing the Hawkesbury River Railway Bridge, before passing through the Central Coast.
At Fassifern, a former branch line to Toronto divided off in an eastwards direction until closed in 1990. The line continues north to Broadmeadow in the inner western suburbs of Newcastle. North of Broadmeadow is the junction with the Newcastle branch line, where electrification of the main line ends. However, electrification continues along the branch line to Newcastle Interchange terminus at Wickham, with the branch line beyond Wickham to the former Newcastle station having been closed and lifted in December 2014.  The line then swings westwards as four tracks; two main line and two coal roads traverse the outer suburbs of Newcastle to Maitland. The two coal roads run to the Newcastle coal lines, which serve a number of collieries along the route. Maitland is the junction of the North Coast line which continues to Brisbane where some argue is a branch line and the Main North line. The line becomes double track immediately west of Maitland and heads through the Upper Hunter Valley townships of Branxton, Singleton and Muswellbrook where the double track ends.
Muswellbrook is the junction point for the former cross country line to Sandy Hollow and Gulgong. The Main North continues northwards through the Ardglen Tunnel to Werris Creek, where the Mungindi Line branches off to Moree, and a former cross country branch continues to Binnaway and ultimately Dubbo. The Sunnyside rail bridge over Tenterfield Creek has fallen into disrepair, 2015 The line continues north, but sees limited traffic beyond Werris Creek. The line reaches the major New England towns of Tamworth and Armidale, the latter being the northernmost extent of service on the line at this stage. Until the mid-2000s freight traffic continued to the disused station at Dumaresq which is home to a now-also-disused agricultural fertiliser depot. There is now various leases to local land owners along the corridor between Armidale and Wallangarra, as the rail corridor is non operational at the moment.
A block is placed across the tracks a short distance from the Armidale railway station. North of Glen Innes the line, and particularly its bridges, have fallen into disrepair. In December 1991 the line was tarred over when the Roads & Traffic Authority built a deviation of the New England Highway over the line at Bluff Rock south of Tenterfield however the track does remain in place. At Wallangarra, the line meets Queensland Railways Southern railway line where there is a break of gauge from standard and narrow.