Recently, the Khlongphai Tunnel in the 3-2 section of the China-Thailand High-speed Railway Project was successfully completed, marking significant progress in the tunnel construction of the project.

The project extends from Bangkok in the south to the Thailand-Laos border in the north, where it connects with the China-Laos Railway. It is Thailand's first standard-gauge high-speed railway. The Khlongphai Tunnel, located in Nakhon Ratchasima province north of Bangkok, spans 4.1 kilometers and is the longest tunnel in phase one of the project. The tunnel construction faced significant challenges, including faults, fractured rock formations, and complex conditions such as karst cavities and caves.