Up to 15.1 per cent of trains were late in February, up from 14.8 per cent in January.

This was in stark contrast to October last year, when only 6.7 per cent of trains did not run on time.

In response, V/Line said heat speed restrictions over summer and trespassers on tracks went some way to explaining a decline in on-time services.

Its trains have reduced speed limits when the mercury tops 36 degrees because steel tracks can expand in the heat.

But the Bureau of Meteorology’s weather station at Ballarat recorded only two days above 36 degrees last summer, when it climbed to 40 on February 9 and 37 on January 17.

Melbourne had eight days above 36.

V/Line chief executive James Pinder said the Ballarat to Melbourne line was one of the regional rail operator’s busiest lines.

“We’re working towards impoving punctuality for passengers on the Ballarat line, and at the same time we’ve added more seats and more services to cater for growing patronage,” he said.

Dramatic video footage emerged last month of a dirt bike rider leaping off the tracks seconds before a V/Line train smashed into his bike as it roared past at 147 km/hr near Ballan.

The driver of the train, Colin Sharp, told radio station 3AW he was left shaken by the incident.

“I reckon as he was going off the side of the bridge he would have almost scraped his boots on the side of my train as I went past him, it was that close,” he said. “I really honestly thought that I had him and thank god that I didn't.

““He was pushing the bike across (a) bridge, which was a pretty silly thing to do.”

It comes after V/Line moved to allocate two bigger three-carriage “Vlocity” trains to the busiest peak hour Ballarat services back in November.