Scorching temperatures have left commuters in Victoria fuming after major delays on the regional and metropolitan train network.
Two signal faults have been reported on the regional V/Line network to Geelong, trapping passengers on busy trains and delaying travel by more than an hour.
Almost all Melbourne metropolitan lines were also affected by delays caused by issues at a level crossing and equipment failures, with some replacement buses taking more than an hour to arrive.
Temperatures peaked at 39C in Melbourne but some parts of the state were already in the early 40-degree ranges with people sweltering through a dangerously hot day.
Nine children had to be rescued from hot cars and more than 1000 homes were left without power on Thursday with people warned to brace for worse conditions.
"The fire risk is real and the fire risk only gets worse with the fact that there's no respite across the state tonight," Emergency Services Commissioner Craig Lapsley said on Thursday.
"It will be potentially 30C at midnight in Melbourne, so it's a hot night."
Mr Lapsley said central and western Victoria were most at risk of bushfires, with blazes already burning near the SA border and Geelong.
Despite extreme heat warnings, Chief Health Officer Charles Guest said there'd been reports on Thursday of nine children being left in parked cars .
"We know that leaving children in parked cars can lead to death. I'm glad to say this hasn't happened this summer so far," he said.
More than 1000 properties in Beaufort, near Ballarat, were left sweltering without fans and air-conditioners because of a power failure before operator Powercor restored electricity.
Dr Guest said people without access to air-conditioning or at risk of heat exhaustion were advised to head to shopping centres or cinemas to cool down.
The Bureau of Meteorology is predicting temperatures in Melbourne to reach 42C on Friday with other parts of the state to see ranges in the low to mid-40s.
"It's going to be dry, hot and a change in the south but the change won't be helping things in the north," the Bureau of Meteoreology's state manager Andrew Tupper said.
He said there would be a risk of dry lightning, which occurs when electrical storms hit without rain managing to make it to the ground.
Total fire bans remain across the Mallee, Wimmera and Southwest districts in the state.
