An "urgent familiarisation drill" led to train services being delayed on the opening day of a major city's long-awaited underground line.

Crowds have flocked to five new underground stations to catch trains through Melbourne's Metro Tunnel for the first time.

All the news from the second day of train services running through the Metro Tunnel on a reduced summer timetable.

The opening of the $15 billion underground train line deserves celebration, but it won’t be a game changer without more ...