Major construction on Sydney's new South West Rail Link has been finished a year ahead of schedule and $100 million under budget, the NSW government says.

Now it just needs people to start using it. The $2 billion, 11.4 kilometre rail line extends from the existing metro rail network at Glenfield to Edmondson Park and on to Leppington. Three years ago it was forecast to cost $2.1 billion and was due for completion in 2015. But…