Is the threat of getting their heads smashed by a concrete ball enough to prevent people from riding the roofs of Indonesian trains?

Depends on whom you ask.

"From our monitoring so far, the roofs of the trains have been clean (from riders) after the concrete balls were put in place,” a spokesman for state railway company Kereta Api Indonesia, Mateta Rizalulhaq, told the Jakarta Globe on Monday.

The devices erected over some train tracks are called Goal Bola-bola, or goal balls, as they resemble soccer goals with the grapefruit-sized concrete balls strung from chains. The balls are about 10 centimeters, or 4 inches, in diameter and are painted silver. They a strung in groups of a dozen each over each track. The first ones were deployed Tuesday.

But in a Globe report on Saturday, Eman Sulaiman, chief of the Bekasi city station, near which the first set of concrete balls were strung last week, said some people are still trying to ride, donning motorcycle helmets for protection.

Passengers are climbing onto roofs after trains pass the obstacles, according to a report Friday in the Jakarta Post.

FULL POST

Indonesia's state railway, Kereta Api Indonesia, has begun stringing concrete balls over rail lines to prevent people from hitching free rides on top of its trains, according to local news reports.

The devices are called Goal Bola-bola , or goal balls, as they resemble soccer goals with the grapefruit-sized concrete balls strung from chains, according to a report in the Jakarta Post.

Trains in Indonesia are often overcrowded.

The railway said it resorted to using the concrete balls after previous anti-roof-rider efforts - including greasing the roofs, spraying roof riders with colored water, and detentions and fines - didn't stop the practice.

But a human rights group says the balls expose violators to a punishment as severe as death for a minor infraction.

“Picture this: If a student has to take the train, he or she would face the threat of being killed by the concrete balls. Now his right to get to school safely is simply violated,” Yosep Adi Prasetyo, a spokesman for the National Commission on Human Rights, told the Jakarta Globe.

The balls will only be used on lines that run locomotives, according to the Globe report. Lines with electric trains will use swinging doors that will allow the electrical connectors through, but not roof riders.

Adi told the Globe the real problem isn't freeloading riders, but that there aren't enough trains to accommodate demand.