(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.

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.

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.

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)

http://www.cnn.com/2008/WORLD/asiapcf/02/10/indonesia.trains/index.html