The Eastern line was originally proposed in 1870.The reason they built it was mostly because of the Southern line. The Newmarket line(Also known as the southern Line) was the only railway at that time that left Auckland central. .Now at this time in 1870,Railways were extremely popular in New Zealand. everyone wanted to catch the train. but on this double track
line railway between Auckland and pukekohe, This obviously meant that traffic was starting to pop up and delays were happening frequently.The solution was simple. to create a bypass railway passing Newmarket and the busy rail traffic altogether. this would obviously be the eastern line.this was a perfect option because it would help ease congestion on the Newmarket line and it would also bring growth to places like Panmure and Meadowbank. the eastern line used to go all the way to Papakura but in early 2012,The Manukau extension was open finally connecting one of Auckland's biggest Metropolitan area's to the CBD.
The eastern has had loads of redevelopments over the years including the Panmure station upgrade and the electrification of its railways. But I must say.I think it has had a very good past, and I am excited to see what the future holds for it.