A piece of paper was the only notice given to a train driver that he should slow down before a derailment north of Melbourne which killed him and another man.
The NSW Trainlink XPT passenger train was on its way to Melbourne from Sydney on February 20, 2020, when it came off the tracks at Wallan soon after 7.30pm.
Experienced driver John Kennedy, 54, and 49-year-old rail worker Sam Meintanis were killed. Eight passengers were seriously hurt and another 58 people sustained minor injuries.
The Australian Transport Safety Bureau's final report into the crash was released on Wednesday and made 37 findings, with 15 in relation to safety issues.
On the day of the derailment, the train was diverted through the Wallan loop track because the signalling system was down on the normal route's straight section.
Instead of entering the loop section at the required 15km/h, the passenger train was travelling at speeds of between 114km/h and 127km/h.
"We know the emergency brakes were applied some 150 metres or so before the turnout," ATSB chief commissioner Angus Mitchell said on Wednesday.
"But that wasn't sufficient to wipe off the speed that was required to navigate that turn."
There was no evidence to suggest the driver was incapacitated or a track defect led to the derailment, the report found.
Instead, it was likely the driver was not aware there was a change of route and he expected to travel through the straight section where the speed limit was 130km/h.
He had been through the straight section of track eight times in the previous 12 days but had never been diverted through the Wallan loop.
The driver was given a piece of paper advising him of the new route but there was no process that required him to confirm with network control he understood the changes.
"There was no system in place to mitigate either a misreading or any other human interaction," Mr Mitchell said.
"A safety system needs to be multi-layered in its defences and it cannot rely on any one piece of technology or one human to be the only defence."
Two V/Line services had successfully made their way through the Wallan loop in the hours before the XPT passenger train derailed.
Network operator the Australian Rail Track Corporation notified V/Line of the changes and it briefed its crews but NSW Trains did not follow a similar procedure, Mr Mitchell said.
"We know that the V/Line system did have greater checks and balances in place," he said.
The bureau found there was too much reliance on administrative controls and the rail industry should instead modernise its safety systems.
Australia's rail safety regime must be urgently reviewed and reformed in light of the findings, Rail, Tram and Bus Union assistant national secretary Shayne Kummerfeld said.
"This was a failure of communication, a failure of process and a failure of risk management," he said.
"We can only hope that this tragic incident spurs genuine change to rail safety processes so that something like this never happens again."
A NSW Trains spokeswoman said the company continued to meet all of the national regulator's safety and accreditation requirements.
"We are always looking for opportunities to do better," a statement to AAP read.
NSW Trains and the Australian Rail Track Corporation have both been charged over the fatal derailment for failing to ensure there were sufficient safety measures.
The case is due to return to the Melbourne Magistrates Court in September.