The railway project comes at a time when a surge in tourist arrivals - more than half the population - has already strained the Thai infrastructure.
In March, the government approved the 225 billion baht ($6.80 billion) rail project that will connect two airports in Bangkok areas - Don Mueang International and Suvarnabhumi International - with U-Tapao, which was built during the Vietnam War in the eastern province of Rayong.
CP Group and its business allies that formed a consortium and expected strategic partners include Charoen Pokphand Holding and China Railway Construction Corp Ltd, Adiruth Thothaveesansuk, vice chairman, CP Group's Special Projects Development Office, said in a statement on Sunday.
According to the statement, the global consortium also includes China's CITIC Group Corp [CITIC.UL], Germany's Siemens, South Korea's Hyundai, Bangkok Expressway and Metro Pcl, Italian-Thai Development PCL, Thailand's CH Karnchang PCL, Japan Overseas Infrastructure Investment Corp for Transport & Urban Development, China Resources (Holdings) Co Ltd, Italy's Ferrovie dello Stato Italiane, China's CRRC-Sifang, and Japan Bank for International Cooperation (JBIC).
Thai conglomerate CP Group is controlled by billionaire Dhanin Chearavanont.
Another bidder, BSR Joint Venture, includes BTS Group Holdings, Sino-Thai Engineering and Construction and Ratchaburi Electricity Generating Holding.
The project is part of the government's larger transport infrastructure investment action plan covering rail, roads, airports and sea-ports.
The State Railway of Thailand (SRT) will take a month to consider the bids and is expected to propose the winner to the cabinet between January 28 and 31, acting governor Worawut Mala said in a statement.
Contract signing is expected in the first quarter of 2019, with construction taking five years, a source at the SRT said.
(Reporting by Satawasin Staporncharnchai; Writing by Orathai Sriring; Editing by Louise Heavens)