The Regulation Governing the Handling of Investigation Procedures for Railway Occurrence Article 6

The TTSB may terminate an ongoing investigation after deliberating its feasibility but shall specify the reasons for such termination.
中文原文 重大鐵道事故調查作業處理規則第6條
運安會經審度調查之必要性後,得於事故調查進行時中止調查,但應述明理由。

English translation for reference only; the Chinese text prevails. Not legal advice.