Pretoria - Punishments meted out to cable thieves and scrap metal dealers need to be much heavier, the Passenger Rail Agency of SA (Prasa) said on Wednesday.
Chief operating officer Lucky Montana said replacing stolen cables cost Prasa R40m a year.
This did not factor in lost revenue from trains unable to operate because of the theft.
"The total cost could be as much as eight times more," Montana said.
He said the cable thieves who brought the rail network in Cape Town to a halt for a day at the beginning of 2010 had been fined R500 each.
The cost to Cape Town's economy as a result of workers being unable to get to work was estimated to be in the region of R300m.
Montana said he believed there needed to be greater regulation of scrap metal dealers buying stolen cables.
"They should lose their licence and be heavily fined."
The penalties for cable thieves were too lenient and consideration should be given to special courts.
Montana said he did not believe the judiciary understood the seriousness of cable theft and its cost to the economy.
"This (cable theft) should be treated as sabotage," he said.