The new train line from Richlands to Springfield will be dual track, Transport Minister Rachel Nolan confirmed last night.
The decision will prevent delays and allow more trains to use the track between the two stations.
Public transport lobby group Rail: Back on Track and Ipswich City Council had pressured the state government to revise their original plan to build one rail line from Richlands and Springfield by 2015.
In the past, both parties said building one line simply meant the Government would have to come back and add extra rail line track when it was more expensive in the future.
Ms Nolan said Government had changed their original concept and would include the link between Richlands and Springfield as dual line.
"The dual track line to Springfield comes in addition to the current project which will create a third electrified track from Corinda to Darra by the end of the year," Ms Nolan said.
"That means more trains, including more express trains, will be able to get through.
"Trains servicing that area can move more frequently and independently of each other. It will allow for better on-time running and more reliable services.
"In other words, it will effectively free up movement in both directions. Trains will no longer be in a holding pattern."
Infrastructure Association of Queensland executive director Paul Clauson last night welcomed the announcement.
Mr Clauson said the decision showed genuine financial commitment.
"This is a positive development for the south-east corner given the population growth and the government's intentions to develop satellite cities in the western corridor," Mr Clauson said.
Last month, Premier Anna Bligh announced three new satellite cities - including Ripley Valley outside Springfield - would be fast tracked to cope with population growth.
Today's Queensland Budget will contain $646 million for the Stage Two works, which includes both the rail line from Richlands to Springfield and widening the Centenary Motorway to four lanes all the way to Springfield.
The first stage of the Darra to Springfield Transport Corridor, from Darra to Richlands, costs around $800 million.