New transport data has revealed Melbourne's least reliable train lines.

The report discovered commuters on the Frankston, Pakenham, Cranbourne and Lilydale lines were slugged with the most unreliable service in 2017.

More than 860 trains were cancelled last year along the Frankston line last year alone, making it the most unreliable line on the network.

Scroll to the bottom to view the full list.

More than 9500 trains have been cancelled on the Frankston line in the last 10 years. (9NEWS)

Glen Waverley, South Morang and Sunbury lines were among the most reliable, with less than 300 trains cancelled last year. (9NEWS)

In the past 10 years, more than 9500 trains had been cancelled on the line.

Glen Waverley, South Morang and Sunbury lines were among the most reliable, with less than 300 trains cancelled last year.

Lilydale commuters were slugged with the highest number of shortened services, with nearly 1700 trips reduced.

Meanwhile, more than 760 trains bypassed the City Loop on the Pakenham line.

Pakenham line customers also battled the worst punctuality, with more than 13 percent of trains not arriving on time.

In total, 6048 trains were cancelled last year across the network.

The hot, crowded trains left some racegoers with no choice but to push open the train doors. (Sean Davidson)

READ MORE: Stranded racegoers recall chaos aboard crammed trains

But despite the cancellations and delays, PTV CEO Jereon Weimar said both Yarra Tram and Metro improved their service delivery in January and exceeded their targets.

"January saw operators deal with the dual challenges of prolonged periods of hot weather and major upgrade works on our road and rail networks," Mr Weimar said.

Metro Trains said 92.3 percent of trains ran on-time, exceeding the newly set target of 92 percent.

Around two million trips are taken on Victoria's public transport network every day.