Many light years away before completion of HST.
SRT's priority at the moment is the completion of double track projects on the current narrow gauge system.
reference Google:
Thailand is upgrading its railway system through a combination of infrastructure projects and technology enhancements. This includes doubling existing tracks, modernizing stations, upgrading signalling and telecommunication systems, and investing in new trains and rolling stock. The modernization efforts aim to improve safety, increase capacity, and reduce travel times, particularly on key railway lines.