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• A KiwiRail engineer experiencing after-effects of Covid-19 failed to stop at a red signal nearly causing a train collision last year. 
• The engineer ran a red light at 44km/h but avoided a crash as track settings kept it on the main line. 
• TAIC has warned of post-Covid cognitive issues affecting safety-critical workers. 

An investigation has found brain fog from Covid-19 likely played a role in a KiwiRail coal train’s near miss with another train. 

Investigators concluded the locomotive engineer was likely still suffering the after-effects of Covid-19 early last year when they failed to stop at a red signal and entered a main line, which was occupied by another train. 

A Transport Accident Investigation Commission (TAIC) report detailed how the loaded coal train bound for Lyttelton, departed Arthur’s Pass on February 27 last year. 

The engineer had taken over Train 850 at the pass station and had been instructed to cross another train at Cora Lynn, approximately 15km to the east. 

The west end of Cora Lynn showing the main line, the loop and signal. Photo / TAIC 

A yellow intermediate signal approaching Cora Lynn indicated that the arrival signal was set to stop, requiring the engineer to bring the train to a halt. 

However, the train continued past the red arrival signal at 44km/h and entered the main line, narrowly avoiding a collision with an opposing train in the loop. 

Fortunately, the points were set for Train 850 to remain on the main line, preventing a potentially serious crash, the report said. 

While the engineer was unable to explain why they failed to stop, they later disclosed that they had recently been unwell with Covid-19 while on annual leave. 

In hindsight, the engineer believed they should not have returned to work so soon, as they were still experiencing lingering effects of the illness, they told investigators. 

The TAIC report highlighted concerns about the impact of acute illnesses such as Covid-19 on cognitive functions like memory and concentration. 

“Medical advice received by the commission was that potential effects of Covid-19 on cognitive impairment [‘brain fog’] are well documented and can be long-lasting, continuing after the infection has cleared,” the report said. 

“The locomotive engineer could not remember the indication on signal 10530 and were unaware that signal 10244 had been passed at stop. Symptoms of cognitive impairment because of a recent Covid-19 illness can include temporary lapses in concentration and a reduced capacity for situational awareness.” 

It recommended that safety-critical workers carefully assess their fitness before returning to duty and called on organisations to recognise the risks posed by post-illness fatigue. 

The engineer in question was required to stop for at least 10 seconds to confirm the track was correctly set, but this step was skipped. 

The error was not immediately reported, as both locomotive engineers involved initially failed to realise a signal had been passed at danger. 

Once the oversight was recognised, the incident was reported to KiwiRail management, triggering an internal investigation. 

The engineer had been employed by KiwiRail since 2012 and was an experienced driver and instructor, the report said. 

The train consisted of two DXC class diesel locomotives, stretching 439m and weighing 1904 tonnes. 

The report noted that weather conditions were clear with good visibility at the time, ruling out environmental factors as a cause. 

Ben Tomsett is a Multimedia Journalist for the New Zealand Herald, based in Dunedin.