Jakarta, Indonesia (CNN) -- Indonesia has long fought a losing battle against commuters who stubbornly ride on train roofs to beat the rush hour. But railway officials say they have found the perfect deterrent, concrete balls, suspended on chains from a steel frame, just 25 cm or 10 inches, above any passing train.
Dubbed "Goal Balls", they are about 10 cm or 4 inches in diameter and are painted silver. Twenty four, a dozen on each side, are suspended from a frame that looks like a soccer goal.
The first one was installed early this week, a few hundred yards from a train station, just outside Jakarta.
Anyone riding on the roof will find it hard to dodge the balls. Mateta Rizahulhaq, a spokesman for the state-owned railway company PT Kereta Api, told CNN no one has dared an attempt it. "From our field reports so far, there have been no roof riders on that line since we installed them," Rizahulhaq said.
Over the years, officials have tried and failed to stop commuters from climbing atop carriages.
"Policing passengers has been going on in various ways for so long. Starting with oil on the roof, using barbed wire, spraying dyed water, dogs, advice from religious leaders. None of these were effective," explained Rizahulhaq.
Some critics say this latest tactic seemed too extreme.
"It's not that we do not have humanity, but from the time someone gets up on the top of the train, they just do not value their life anymore," Rizahulhaq added.
Almost half a million commuters depend on the railway system to travel within the greater Jakarta area. Trains are packed, especially during the rush hours.
Many passengers choose to climb to the top of overcrowded carriages. There are some -- train surfers -- who get on for a free ride or just for the thrill of it.
Officials say these thrill rides cause one or two deaths per month. They hope the new measure will prevent any more fatal accidents. If the concrete balls prove to be effective, more will be installed in other areas of the capital, officials said.
The government predicts that by 2018, the number of train passengers in Jakarta will increase to over a million. Everyone here agrees that what this growing metropolis needs is an improved and expanded railway system that gives passengers no excuse to get on train rooftops.