Commuter Line Train

Another way to overcome the Jakarta's traffic is by riding the train or KRL commuter line. It is a commuter rail system connecting Jakarta and its satellite cities. The electric train service passes stations across Jakarta, Bogor, Depok, Tangerang, and Bekasi and also have two special carriages reserved for female passengers on either end of the train for an extra convenience.

Commuter Line Train is a commuter electric rail service that is operated by PT Kereta Commuter Indonesia, a subsidiary of PT Kereta Api Indonesia (PT KAI).
Come as a traffic solution in Jakarta, the travel time needed by KRL is also much shorter than other public transportation. The costs required to use this public transportation are also very affordable
The Commuter Line serves around 80 stations with 6 transit stations in total that will bring passengers to the the heart of the city including Kota Tua, Sudirman, Cikini, Tanah Abang, and Pasar Senen, which are close to various tourism sites.
As the trains are usually packed during peak hours along the week, so you may want to avoid taking the train around 7-8am and 6-7pm, it best to use it during non rush hours and weekends. 
It’s easy to find a train station in Jakarta as now it covers a very wide area of the city. It’s very cheap too, costing 5,000 IDR less or more to travel to a corner of the city.
Local tip: Train stations may not have dedicated platforms for trains going different lines, so make sure you know what trains to take before boarding.
The types of KRL tickets you can choose are:
1. Single-journey cards
Single-journey cards or THB is an electronic KRL ticket that you need to buy if you want to take one train trip on the same day. The price of this THB is Rp.10,000 (the price of the card subsidy) plus the fare of the KRL route you choose. Safe, prepare money around 13,000 to 20,000 rupiah
2. Multi Trip Cards
Multi Trip cards, or KMT, are electronic KRL tickets that you can use repeatedly with unlimited time, as long as your card balance is still there. The minimum balance of KMT is 5,000. The initial price of this card is Rp. 50,000 with a balance ofRp. 30,000. If your balance runs out, you can refill it yourself in the KMT balance filling machine available at the station.

3. Bank Cards & E-Money
A prepaid bank card or e-money users, surely can use cards like Mandiri E-Money, Brizzi, BNI TapCash, and BCA Flazz. In addition you can fill it before leaving for the station, using a bank card will also prevent you from long queue at the ticketing window.
With the e-ticketing system Commuter Line users can be more orderly and comfortable to travel. This e-ticket is divided into two types, Multi Trip Card (KMT) and Single-journey cards (THB). this e-ticketing system we can also be accessed by scanning the QR code.
After the trip is complete, you can immediately refund this card at the ticket purchase counter. But this card has a validity period of only seven days, if during this time you do not use this card, this card will automatically expire and cannot be used.