See the timetable for the KTM KL Sentral to Port Klang (Pelabuhan Klang) Komuter train, which leaves from the city centre to the coast where you can take ferry boats over to Sumatra in Indonesia (boats leave for Dumai and Tanjung Balai Asahan).
Port Klang KTM station is the last stop on this Klang Valley commuter route and the station is located just across the road from the ferry terminal, making connections to boats easy.
The duration of the trip from Kuala Lumpur Sentral is a little under one and a half hours, with the first train leaving in the early morning, until the last service late in the evening.
New train timetable valid from the 3rd of February 2018:
|Departs KL Sentral||Arrives Port Klang|
You can use these commuter trains to travel from KL Sentral to: