This is old news, but I thought I'd post here to see if anyone else has heard about this, I could find nothing. Basically, Phnom Penh doesn't have a public transportation network, despite at least a few attempts to create one. Just as JR rolling stock finds its way to southeast Asia, it seems that some buses do (did), too. Phnom Penh's last crack at a bus system was in 2001 with retired Osaka City buses. I wonder what became of them. I couldn't find any pictures.
http://www.bbc.co.uk/news/world-asia-16343191