"These trains are moving in some cases at up to 100km/h - there is no chance of the driver pulling it up and avoiding you being hit," he said. "In some cases we have seen people with permanent disabilities as a result of doing crazy things in the rail corridors."

In some incidents, children had played chicken with 400-tonne trains as they passed rail crossings.

People caught trespassing on the rail corridor face a $5500 fine, while those responsible for damaging or spraying graffiti on trains face up to 12 months' jail.

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Sydney Trains chief executive Howard Collins said the rail operator had 12,000 closed-circuit TV cameras in place across the network and would work with police to track down trespassers.

"Some of the footage I have seen is heart stopping, even in the 42 years I have been in this business," he said.

"We continue to chase these idiots who like to hang onto the back of trains.

"Don't do it - you will die and, as a result of that, your family will be traumatised."

Mr Collins said staff who had to deal with the tragic consequences of trespassers being hit by trains were often unable to work again due to the trauma they suffered.