Melbourne train derailment: Clifton Hill train derailment investigation leaves key questions hanging

A key section of track was repaired just four days before a train derailed at Clifton Hill causing a network-crippling service outage.

The Australian Transport Safety Bureau on Friday released a preliminary report into the derailment of the last city-bound Mernda train on Sunday, July 13.

It confirmed early theories that a bogie – a series of four wheels – on the train’s fifth carriage had derailed as it travelled over the High Street/Queens Parade.

But ATSB chief commissioner Angus Mitchell said further investigation was required to figure out exactly why.

“This will include further analysis of the condition of the rolling stock – focusing on the wheel and suspension components – and the track condition, including the recent maintenance and track replacement work that was undertaken