The loco crew were enjoying the drive out of Melbourne on a nice hot day when confronted by a buckled rail.
It was a rough ride for a few moments but the loco and train stayed on and the crew were as James Bond would say ” shaken not stirred”
Buckling happens when the track heats up, every time it gets way too hot outside, which for Australia, is pretty much all the time and the steel expands and shifts rapidly.
If the track does buckle, the line must be closed and the track repaired before services can resume, causing considerable disruption. Usually, these repairs can’t be done until the temperature of the rails has dropped.