Adi Weda / EPA

Passengers taking a nap on the roof of a commuter train in Jakarta, Indonesia, Jan. 19.

Romeo Gacad / AFP - Getty Images

A train loaded with passengers heads to central Jakarta during rush hour on Jan. 18.

AP reports from Jakarta, Indonesia:  Indonesia has gone to imaginative extremes to try to stop commuters from illegally riding the roofs of trains — hosing down the scofflaws with red paint, threatening them with dogs and appealing for help from religious leaders.

Now the authorities have an intimidating and possibly even deadly new tactic: Suspending rows of grapefruit-sized concrete balls to rake over the top of trains as they pull out of stations, or when they go through rail crossings.

Authorities hope the balls — which could deliver serious blows to the head — will be enough to deter defiant roof riders.

Adek Berry / AFP - Getty Images

A worker installs an iron support with hanging concrete balls, located across a rail road track in Bekasi district east of Jakarta on Jan. 18, 2012 to deter train surfers.