That's how much of the new 11-kilometre track for the South West Rail Link has been laid as of a week ago.

The new track will connect the two new stations at Edmondson Park and Leppington to Glenfield and the city via the East Hills Line.

A spokeswoman for Transport NSW said the project team took advantage of rail shut- downs over the past six weeks to carry out work in the rail corridor and Glenfield station. "One of the most important activities completed in December was the installation of around 100 beams, each weighing between 14 and 24 tonnes, on the southern flyover," she said.

"Other work carried out included building a new Platform 4 at Glenfield station and work on the northern flyover.

"To minimise disruption to commuters, track installation at Glenfield has been carried out during planned rail shutdowns of the East Hills and South lines.

"Further track installation will be carried out after the completion of civil structures at Glenfield." Early work on the Hume Highway rail underpass (pictured) has started and will continue until the end of February.

"This work . . . involves earthwork, upgrading the road cross-overs, drainage work and line marking," she said.

Construction of the actual underpass is expected to start mid-year.

The spokeswoman said the rail link was progressing well and construction was on track for services to start on it in 2016.

"Around 300,000 additional people are expected to reside in the South West Growth Centre in the next 30 years," she said.

"Further development of public transport services is essential to support this projected population growth."

Transport Minister Gladys Berejiklian visited the South West Rail Link Community Information Centre at Glenfield last week.

She met with Glenfield small business operator Frank Bakir to celebrate, as he was the 2000th visitor.