At about the same time, another V/Line train was travelling on the same stretch of track in the opposite direction with 166 passengers on board.
The trains were supposed to cross using a loop track at Marshall, but a controller in Melbourne made an emergency call urging them to stop when he realised one driver was passing danger signals. The two trains were 940 metres apart at the time.
An Australian Transport Safety Bureau investigation has found nicotine withdrawal was the likely explanation, because the driver had not applied a nicotine patch that day.
The effects of nicotine withdrawal become apparent within a few hours of using the substance and include concentration and memory issues.
“To minimise adverse impacts, attempts by safety-critical workers to stop smoking should be managed under medical supervision,” ATSB chief investigator transport safety Chris McKeown said.
The driver also tested positive for inactive metabolite of cannabis, with levels suggesting he had used the drug in the previous seven days.
The ATSB could not determine whether that cannabis use had affected his performance as well.
V/Line has since installed a protection system at Marshall that could stop trains that pass signals at danger.
Rail operators should consider fitting similar systems at similar single, bi-directional tracks that may pose a heightened risk of issues, the ATSB said.