Promised by government as part of 2006 MOTC plan.
In an ATRF paper Dr Paul Mees says it's not needed and better scheduling and punctuality was sufficient. He presented an alternative timetable.
Then rail operator Connex refutes Mees' paper, publishing a response on its website. It says Mees understated usage numbers and the proposed timetable was inefficient and was not possible to implement.
Some parts of the project were done but the third track did not proceed as envisaged. Wikipedia article.
The government introduced 'Early Bird' free before 7am metropolitan rail travel to try to spread the morning peak.
Note: This item added subsequently for posterity
Bus stop in Werribee
Bus stop in Werribee - closer shot