When I was in Jakarta last week, I used the rail link. My foreign credit card wasn't accepted since a PIN is needed to completed the transaction, but my debit card was fine. Also, I found that not too many people use the train, at least on the occasion I used it. Though I was somewhat shocked that a lady my age (mid-20s) decided to sit next to me when the two rows in front of my own were empty. I though for a moment or two I was possibly being marked, but she ended up getting off on the second stop. Overall, it's a nice way to get to the city center and would take it again if I visit Jakarta once more.