One test train recently reached 110km/h on the elevated section between Rouse Hill and Kellyville in the Sydney suburbs to evaluate train stability and braking capabilities.

So far, Alstom has delivered 10 of the fleet of 22 six-car trains, with 10,000km of test running already completed.

Reliability, braking and performance testing is due to be extended soon to include the new 15km twin-bore tunnel between Bella Vista and Epping.

The first stage of the Sydney metro from Rouse Hill to Epping and Chatswood is due to open in the second quarter of 2019.