"But what is going to motivate a future decision around this is actually the capacity of the existing T1 western rail line,because it reaches full capacity by 2030 – you can't put any more people on the trains."
The Baird government has promised to increase the number of trains running each hour by two to 20 on the western line by 2019"to try to build capacity into a very constrained rail line".
"That is our focus at the moment but,given the growth in the city's west,the realistic long-term outcome is going to have to be considered,"he said.
The western line is the busiest on Sydney's rail network. The most recent government statistics showaverage loads on the line in the morning peak surgedby 21 percentage points to 134 per cent between September 2014 and September 2015.