Lightning strikes cripple Melbourne's signal system

Melbourne's train system will continue to fail in foul weather until its ageing signals are replaced with newer, more reliable technology, says the head of Public Transport Victoria.

The rail meltdown that caused chaos and severe delay for commuters all over Melbourne on Monday morning has been blamed on multiple signal failures brought about by lightning strikes and local flooding.

"When you get very intense lightning strikes, our signalling system is relatively old and it can't cope and ... it puts all the lights onto red and it stops all of the trains," Mr Wild told 774 ABC Melbourne.

"Clearly, going forward this is one of the main reasons we need to invest in a new signalling system," he said.

Melbourne's patchwork of "traffic light" and copper wire signals is up to 80 years old and have proven vulnerable to attack from a range of forces including electrical storms, copper thieves, rodents and a flying bat. On each occasion an isolated signal failure has caused a domino effect that has delayed dozens of trains and inconvenienced thousands of train travellers.

The Public Transport Users Association argues Melbourne should switch to a contemporary radio-based signalling system, which is less vulnerable to external attacks and has the important benefit of increasing capacity because trains can safely run closer together.

Radio-based signalling puts the signal inside the train driver's cabin instead of beside the tracks. The technology is a crucial aspect of the planned $2 billion to $2.5 billion upgrade of the Cranbourne-Pakenham railway lines.