Trains run in South Sumatra between Tanjungkarang, Palembang, and Lubuklinggau in North Sumatra between Medan and Aceh; and in West Sumatra between Padang and Bukittinggi. Don't reserve train seats on a train that's going to arrive because the seats are already full and people won't move. Only reserve seats on a train which is beginning from the station you're in. flights: Caltex runs charter flights out of their oilfields in South Sumatra and you could get a free ride such as from Jambi to Tanjung Pinang (Riau) or from Jambi to Jakarta. Mobil Oil Co. works most of North Sumatra and they have the same thing going. Sometimes Indonesian air controllers will ask for money to get on one of them or charge you before they'll tell you about them. But it really could be free.