By Lucy Williamson
BBC News, Jakarta
Rush-hour trains in Jakarta are sometimes so packed that people are forced to hang in the open doorways - clinging to life by their fingertips.
Guards patrol stations armed with canisters of coloured liquid
Another option is to get up on the roof and crouch below the black electric pylons until you reach your stop.
But starting this month, guards are patrolling the stations, armed with canisters of coloured liquid.
Their aim is to spray-paint anyone riding on top of the trains, to get some discipline back into the railways.
It's not actually paint they are using - it's food colouring, mixed with water.
But nevertheless, it is pretty nasty stuff.
Spray them all over
In the back office at Manggarai station, the team preparing the mixture told me it made victims' eyes water and their skin itch.
I asked them if they aimed for any specific part of their targets. "No," was the answer, "we spray them all over."
It is not pleasant, but this new scheme is something of a last resort for Jakarta's railways.
Twenty-three people were killed in the capital last year - either from electrocution or by falling off the top of the train.
Large warning signs have not worked; neither have the regular security checks.
But after just two weeks of the new scheme, the problem at Manggarai station has been all but wiped out - and that has made team-leader Yulianto very happy.
"I was sick of all those passengers who would start acting up, and shoot their mouths off, and throw things at us" he said. "One time, someone threw a bottle at an officer and cut his face."
No room in the cabin
Commuters often have to squeeze into packed rush-hour trains
But it is not just trouble-makers and fare dodgers who ride on top of the trains.
One of those caught earlier this month was Yanto.
He is a construction worker, and if he is just a couple of minutes late for his early morning shift, he - and his family - lose half a day's pay.
He told me he had climbed on top of the trains because there was no room in the cabin.
"I think it's much safer for us to be up there rather than inside," he explained, "because everyone's pushing each other down there and you can't hold on to anything".
Yanto now has to get a letter from his local government office saying he will not do it again. If he does, he could face a hefty fine, or even a three-month jail term.
Warning signs have not stopped passengers riding on the roofs
Tough conditions, but most commuters fully support the scheme.
"People get electrocuted all the time," one man told me as he clung to the doorway of his train. "It's a good idea," another man said.
So it seems the Jakarta railways have found their solution.
But would it work elsewhere? In the UK for example?
Yulianto thought about this question, and then smiled: "From what I know, passengers in the UK are all very orderly and disciplined.
"They don't need to have this kind of programme there; this only applies to Indonesia."