(CNN) -- The risk of being jolted by 1,500 volts of electricity hasn't scared them off. Neither have fears of falling off the speeding electric trains.
Thousands of passengers ride on overloaded trains in Jakarta every day.
So Indonesian railway officials on Monday will unleash a new weapon on commuters who squat on top of railway cars: spray them with colored dye, a local newspaper reported.
The state transit agency told the English-language newspaper Jakarta Post that it hopes the "unique approach" will deter passengers riding illegally on rooftops.
Trains are the cheapest and fastest form of transportation for office workers commuting between the capital city Jakarta and neighboring towns.
Throngs of thousands cram the trains during the morning and evening rush hours, making it impossible for everyone to snag space inside packed cars.
Under the new plan, security officials at each station will "mark" roof riders with dye as trains depart. When the passengers disembark at their destination, officials can then easily identify them.
"We will confiscate their IDs and give them a ticket," Akhmand Sujadi, regional spokesman for the transit agency Kerata Api, told the newspaper. "We will send a copy of the ticket to their family, their local neighborhood unit head, their employer, or, if they're students, their headmasters."
The offenders can reclaim their ID cards once they write a letter "regarding their behavior, to be signed by the person who received their ticket."
More than 320,000 passengers rode trains to and from work every day last year, the newspaper reported. The crush of passengers meant revenues of 248 billion Rupiahs ($26.8 million) for the system.
But many commuters prefer to ride on top of passenger cars -- either due to a lack of space inside or because they can't afford the ticket, which start at 1,000 Rupiahs ($0.11)
At least 53 rooftop riders died in the last two years, the newspaper reported. E-mail to a friend