The Taiwan Transportation Safety Board (TTSB) published the Final Report on the investigation of TRA’s Train No.177 at Zhunan Station.

On May 28, 2022, Train No. 177, Tze-Chiang Limited Express Train of Taiwan Railways Administration, MOTC (TRA), departed from Hualien Station at 1446, estimated to arrive at the terminal station Dounan Station at 2129. The underframe of the Car No.11 was on fire and discharged with smoke when the train entered Zhunan Station at 1929. The station staff put out the fire with a dry powder extinguisher. No casualties were reported in this occurrence.

In accordance with the Transportation Occurrences Investigation Act, R.O.C., and the definition of major transportation occurrences specified therein, the Taiwan Transportation Safety Board was the independent agency in charge of investigating the railway accident. The agencies (institutions) invited to participate in the investigation include the Railway Bureau, MOTC and TRA. The investigation report was published on July 19 and was approved by the 52nd Board Committee Meeting on July 7, 2023.

On the basis of comprehensive factual information and analyses, TTSB proposes the following 10 findings and 5 recommendations:

Findings

Findings Related to Probable Causes

1. During the troubleshooting of an overheated axle at Hsinchu Station, the inspectors isolated the parking brake of the bogie at Car 11. They only released the mechanical release device of the overheating axle but did not release the other mechanical release device of the same bogie. As a result, the brake shoe remained in contact with the wheel treads, causing continuous friction and leading to the generation of visible flames before reaching Zhunan Station.
2. Due to continuous contact and friction between the brake shoe's iron accumulation and the wheel tread on the mountain-side of the faulty axle, excessively high temperatures were detected for both the wheel and axle at Qidu Station.

Findings Related to Risk

1. The TRA has no criteria for determining and handling procedures for overheating of wheel tread and does not consider the factor of iron accumulation, which is not conducive to maintenance personnel identifying the actual cause of an overheating wheel.
2. The TRA staff in charge of monitoring the detection device only notified the train inspectors that the axle was overheating, but did not pass the information that the wheel tread was also overheating, which affected the train inspectors to conduct a complete inspection.
3. The troubleshooting procedure for the parking brake does not clearly indicates the amount and location of the mechanical release device that must be released after isolating the parking brake cock, which is not conducive to the complete implementation of the isolation procedures by the inspectors.
4. The content of the train inspector’s troubleshooting training course for parking brake does not provide detailed explanations and practical operations for each type of train, which makes it easy for train inspectors to make omissions when dealing with trains that are not maintained by their own depot.
5. The TRA has not regulated a work party supervisor system for train inspectors when performing troubleshooting, and cannot clearly assign tasks before work and conduct completion inspections after work.
6. The ”Axle Temperature and Pantograph Automatic Detection Device Management Instructions” issued by the TRA does not stipulate that the driver should be notified when the axle and wheel tread is overheating, the driver may easily fail to respond in a timely aspect, thereby increasing the risk of axle overheating.
7. The TRA does not establish the standard for the axle temperature sticker replacement, resulting in stickers failing to indicate the actual axle temperatures when the temperature is raised.

Other findings

1. The locomotive dispatcher should have notified TTSB for investigation when they learned that the train was on fire. However, they still contacted the train inspectors to carry out troubleshooting; in addition, the wheel of the accident train had been milled by the depot staff before the investigation was completed. These two events caused damage to the accident evidence, which affected investigators' evidence collection and further analysis. This shows a lack of clarity among TRA dispatchers, inspectors, and related personnel regarding the scope and regulations of major railway accident investigations. The incomplete preservation of accident trains hinders the subsequent investigation in clarifying the causes of the accident.

Safety Recommendations

To Taiwan Railway Administration

1. Urge manufacturers to prevent brake shoe iron accumulation. To reduce the risk of wheel overheating and tread damage caused by friction of iron accumulation, if iron accumulation cannot be completely evitable, additional procedures for inspecting and addressing iron accumulation should be implemented.
2. Clarify the procedure to stipulate that the driver should be notified when the axle is overheating, and the mechanism for axle temperature sticker inspection and maintenance to ensure effective monitoring. This will prevent situations where train drivers continue operating trains without timely warning information, which could lead to axle overheating. Meanwhile, reduce the risk that the train inspectors cannot correctly verify the axle's temperature due to the failure of axle temperature stickers.
3. Enhance the education and training of parking brake troubleshooting for train inspectors and establish the work party supervisor mechanism to prevent train inspectors from being unfamiliar with the parking brake troubleshooting procedures and mitigate the risk of operational errors due to the absence of a work party supervisor who is responsible for overseeing the operations. Such measures will contribute to ensuring the accuracy and completeness of the troubleshooting process.
4. Disseminate the “Transportation Occurrences Investigation Act” and the “Scope of Major Transportation Occurrence”, and establish a mechanism for preserving accident evidence to prevent destruction during the investigation, which is not conducive to investigations.

To the Railway Bureau

1. In accordance with Article 41 of the Railway Law, the Railway Bureau of the Ministry of Communications may include safety recommendations related to training and regulation revision in regular and irregular inspections and supervise the TRA to execute the safety recommendations.

Vivi Yang, Secretariat Office
Tel: +886-2-7727-6217
E-mail: viviy2314@ttsb.gov.tw

Steven Wu, Railway Occurrence Investigation Division
Tel: +886-2-7727-6260
E-mail: stevenwu@ttsb.gov.tw