A multi-billion dollar rail construction project in Sydney will be finished one year ahead of schedule and will come in more than $100 million under budget, the state government has boasted.

In a joint statement released on Tuesday, State Premier Barry O’Farrell and Minister for Transport Gladys Berejiklian said the South West Rail Link was on schedule to be finished in 2015 rather than 2016 at a cost which would come in more than $100 million below the original $2.1 billion budget.

Berejiklian says the project team has finished installing the 53,000 rail sleepers as well as 31 kilometres of track on the last section of the line, and that 10 of the project’s 14 bridges are complete.

“Over the coming months, the project team will be finishing construction of the station buildings, installing overhead wiring, and installing rail signalling and communications systems before the new line is tested and commissioned,” she said.

Commenced in 2009, the new rail link is expected to serve as the primary vehicle of transport infrastructure in the Sydney metropolitan area’s South West Growth Centre. It will connect with the existing rail network at Glenfield and the growth suburb of Leppington via Edmondson Park.

In addition to 11.4 kilometres of new rail (twin track), the project includes new stations at Leppington and Edmondson Park, a train stabling facility at Rossmore and upgrades to the existing Glenfield Station, including new parking and north and south flyovers.

The second stage of the project, comprising the aforementioned line, new stations and stabling facility is being delivered by Leighton subsidiary John Holland, which says the works involved movement of more than one million cubic meters of earth as well as retaining walls, five overbridges and seven underbridges including an underpass beneath the Hume Highway.

Berejiklian said the progress of the development is encouraging.

“Today’s announcement is the result of that focussed effort and it follows the early opening of Glenfield Station and transport interchange in September 2012, four months ahead of schedule,” she said.