The line fell below the 92 per cent target for trains running on time, with just 83.7 per cent of services arriving in a timely fashion.

V/Line CEO James Pinder said train speeds were capped at 90km/h when temperatures reached above 36 degrees, and some services had been replaced by coaches for part or all of the journey.

“Safety is our number one priority so heat speed restrictions are enforced on really hot days because the steel tracks expand in the heat,” he said.

Victoria experienced its fourth-hottest Januaries on record, Bureau of Meteorology data showed.

Warrnambool’s average maximum temperature for January was 26.3 degrees – 1.8 degrees higher than the long-term average.

Mr Pinder also pointed to the stark difference between the results from last month and January last year.

Just 12.6 per cent of Warrnambool line trains ran on time in January 2017, which V/Line said was caused by speed restrictions put in place after a collision between a train and a truck at Pirron Yallock in July 2016.

The CEO said the results were 71 percentage points higher, and pointed to the completion of works on the line.

“A total of 22 level crossings have now been upgraded on the line, significantly boosting safety for motorists, passengers and communities and allowing trains to run faster,” Mr Pinder said.

“We also introduced a new Warrnambool line timetable at the end of January, with improved journey times for passengers that has bedded down really well.”