Three cleaning staff were killed and one was injured after being struck by a train on Shaoxing Metro Line 2 earlier this month, according to an official statement released by the operator on Thursday.

The incident occurred around 11:40 pm on Sept 13 during non-operating hours. Four cleaners were crossing the tracks when they were hit by a train returning for maintenance. Despite emergency medical treatment, three of the workers succumbed to their injuries. The fourth is in recovery.

The Shaoxing Rail Transit Group, which operates the metro system, stated that preliminary investigations indicate the cleaners had entered the main line area without following prescribed routes. The accident is classified as a production safety incident, which also exposed shortcomings in the company's management responsibility implementation.

In its announcement, the company expressed grievous sorrow over the incident and confirmed that bereavement arrangements for the victims were completed by Sept 17. The operator has initiated a comprehensive safety inspection campaign and pledged to enhance employee training and revise safety protocols. Authorities are continuing their investigation, and further results will be made public.