Bangkok to Aranyaprathet (for Cambodia)

Above: The morning train from Bangkok arrives at Aranyaprathet. Photo courtesy of Michael Allsop.
Aranyaprathet, 255 km from Bangkok, is just 15 km from the Cambodian border post at Poiphet from where buses run to Siem Reap and Battambang for the Cambodian train to Phnom Penh. See the Cambodia page for information about onward bus transport to Phnom Penh & Seam Reap (for the Angkor Wat temples) in Cambodia, and about onwards bus transport from Phnom Penh to Saigon in Vietnam. Trains 275-280 have 3rd class seats, but Thai 3rd class is quite clean and comfortable, and in fact a very pleasant way to travel. Train 279/280 is a diesel railcar. Bangkok ► Aranyaprathet Aranyaprathet ► Bangkok Train number: 275 279 Train number: 280 276 Class: 3 3 Class: 3 3 Bangkok (Hualamphong) depart: 05:55 13:05 Aranyaprathet depart: 06:40 13:55 Aranyaprathet arrive: 11:35 17:35 Bangkok (Hualamphong) arrive: 12:05 19:55 Fares Bangkok to Aranyaprathet (255 km): 58 baht (£1 or $1.50)
No reservation required - just turn up, buy a ticket and hop on.
SOURCE: SEAT61
http://www.seat61.com/Thailand.htm#Aranyaprathet