Has anyone seen anything around where the extension may go? I'm thinking possibly north through Badgery's creek (new airport station?) and then either an interchange with the Western line between St Mary's and Werrington, or just join onto the end of the quad at St Mary's and run a loop back into the CBD. This whole area (north and south of St Mary's) is a near-term growth area.
I've seen two options somewhere. First one is to keep heading straight west to Luddenham, the other to Bringelly. Both are obviously way out in the sticks in the middle of cattle farming territory right now, so unlikely much will happen there for many years. There's Oran Park development happening putting 20K houses in that area over the next 10 years, so there's a possibility of that being a destination too, though the plans that they display everywhere don't show any sign of rail.