Kowloon-Canton Railway will progressively replace the existing voltage transformers on its trains with oil-free and explosion-proof ones, after a probe revealed the West Rail train fire in February was due to a voltage transformer's hidden production imperfection.

Presenting the investigation findings today, Kowloon-Canton Railway said when such imperfections are subjected to a voltage surge, such as lightning, they may surface and worsen, and eventually fail. Tests and monitoring results of other in-service transformers confirmed the failure was an isolated case.

Isolated case

The Government Expert Panel - with representatives from the Railway Inspectorate, Electrical & Mechanical Services and Highways Departments - also considered the transformer's failure a random event basically caused by a hidden insulation imperfection introduced in it production. If insignificant, the imperfection might slip through the production-acceptance test and the transformer would still have worked within the performance tolerance.

The panel concluded the incident was an isolated case and did not reveal a systematic problem. Noting other West Rail train equipment has been designed and built to withstand lightning, the panel said under normal conditions, all train equipment would operate safely even when there is lightning.

The railway has stepped up its monitoring regime, and will replace existing voltage transformers with oil-free and explosion-proof ones which can withstand a higher voltage surge and are therefore more resistant to lightning strikes.

Improvements proposed

Police, the Railway Inspectorate, Fire Services and Transport Departments reviewed the railway's handling of the incident, and proposed some improvements.

The improvements cover:

* West Rail Operations Control Centre's communication with the Fire Services Department;

* the performance of Kowloon-Canton Railway's liaison officers;

* isolation of traction power to facilitate fire-fighting;

* assistance offered to passengers;

* signage inside train tunnels;

* public education on evacuation; and

* staff training.

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The Kowloon-Canton Railway has committed to making efforts to enhance West Rail's safety and improve incident-handling.The Railway Inspectorate will monitor the implementation of improvement measures.