It has, however, said it would reserve space for a future line by digging a rail tunnel and station cavity into the site as part of earthworks preparation. The upgrade would make the journey from Wollongong to Central take just 66 minutes. Credit:Ryan Stuart Brendan McRandle, the executive director of the western Sydney unit in the Department of Infrastructure and Regional Development, said space would be left for four rail tunnels – meaning two separate train links – and two stations. This leaves open the possibility that future governments could both extend the South West Rail Link from Leppington to Badgerys Creek and build a separate direct rail service to other centres – for example, Parramatta. "In the first part, it's planning on the Badgerys Creek airport site to have sufficient corridor capacity for four tracks, to allow for a combination of suburban as well as heavy rail," Mr McRandle said.

"So the airport plan and the EIS [environmental impact statement] that were delivered at the end of last year included a transport corridor that would come in before the airport and it would retain that level of optionality while the government is working through the options to determine the best course of action for both the near-term and long-term transport options for the airport." Mr McRandle said room for one station box would be left at a planned business park near the airport, and another where the terminals would be. The federal and state governments are currently undertaking a joint study exploring options for rail services to the proposed airport at Badgerys Creek and in western Sydney. Mr McRandle said it included examination of metro, light rail and heavy rail, as well as an extension to the existing transport network. A report showing the costs, funding and challenges of the different options is expected to be released around the middle of the year.

The fast rail conference coincided with the release of a report outlining four route options for fast rail between Parramatta and the CBD, which could then connect to the Badgerys Creek via either Liverpool or Blacktown. Commissioned by the Sydney Business Chamber's western Sydney branch and Parramatta Council, the report found fast rail could reduce the travel time between Sydney and Parramatta to 15 minutes and between Parramatta and Badgerys Creek to 25 minutes. The report only considered the routes in broad terms and did not examine how much they would cost or who would pay for them. Infrastructure Minister Paul Fletcher said value capture – a model of financing that aims to use the uplift property owners get when public transport is built near by – had the potential to allow a rail link to Badgerys Creek to be built sooner that it would otherwise have been built. The government, he said, was considering whether the public sector should be bolder in employing such mechanisms and how public sector organisations could use their own property assets to realise value uplift.

Lucy Turnbull, the inaugural head of the Greater Sydney Commission, drew on her own experience of catching the train from Sydney CBD to Parramatta to caution that ticket pricing would be important in the success of any new train lines. "The $3.37 train from close to the city centre to Parramatta is really good value, so whatever new service is delivered in the fullness of time, it will have to compete for price, because I'm not sure whether I would pay $20 if there was an alternative," Ms Turnbull said.