Also, just found Cambodia Trainspotter Blog. Wondering why there is no planned line between Siem Reap and Phnom Penh? Future of Cambodian Rail video by Toll. From what I understand Toll Royal is an Australian company?
The Royal Government of Cambodia has outsourced its railway operations under a 30 year exclusive concession for Toll (Cambodia) Co., Ltd (Trading as Toll Royal Railway) to operate the Cambodian Railway Network. The ADB and AusAID have agreed to fund US$140m network and infrastructure upgrade, the upgrades include South Line (254 Km) from Phnom Penh to Sihanoukville, the North Line (388 km) from Phnom Penh to Poipet (line rehabilitation) and the Missing Link (48 km) from Poipet to Sisophon (line reinstatement). Also included in the funding was provision for infrastructure including the construction of new inter-modal freight terminal on outskirts of Phnom Penh (Samrong).