sentences:  While the original project to construct the line was known as the "Northern Suburbs Transit System", all subsequent projects involving additions or upgrades to the line have carried the same name.The project was estimated to cost $220 million (1989), including $130 million (1989) for infrastructure including earthworks, bridges, and stations.A further $90 million (1989) would be spent on the purchase of a 22 additional two-car electric trains,now known as the A-series train.