The Taiwan Transportation Safety Board (TTSB) released the final report on the investigation of Taiwan Railway Corporation, Ltd. (TRC)’s Train No. 4816 occurrence at Lingjiao Station

At 10:50, February 12, 2024, the first two axles of car 3 of the Local Train No. 4816 derailed at Lingjiao Station, New Taipei City. There were no fatalities or injuries 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 Ministry of Transportation and Communication (MOTC), the Railway Bureau, and the TRC. This final report was reviewed and approved by the 76th TTSB Board meeting on June 13, 2025, and published on July 17, 2025.

Findings

Findings Related to Probable Causes

1. The third car (DR1032) of the train experienced a significant reduction in vertical wheel load on the right wheel of the first bogie due to a malfunction of the air spring leveling valve. Additionally, the poor track geometry in the derailment section further reduced the vertical force on the same wheel, potentially resulting in the wheel treads losing contact with the rail surface. Moreover, a guard rail that should have been installed in this section was absent. While DR1032 was operating through this section, the minimum derailment coefficient threshold dropped below international safety standards, resulting in the right wheel of the first bogie climbing the rail at mileage K10+152 and derailing to the right in the direction of travel.

Findings Related to Risk

1. The installation criteria for guard rail, as specified in the “Track Maintenance and Inspection Regulations for 1067 mm Gauge,” are inconsistent. The TRC’s interpretation of these criteria led to the absence of a guard rail in the derailment section, which increased the risk of wheel climb derailment.
2. Although the TRC possesses equipment capable of measuring wheel loads, it has not implemented any wheel load management measures. As a result, it missed the opportunity to proactively detect and address abnormalities in advance, failing to prevent the risk of a train with unbalanced wheel loads derailing while operating on the main line.
3. The TRC has not established time limits for rectifying track irregularities that exceed emergency maintenance thresholds. Additionally, post-maintenance inspections are conducted only at isolated points, making it difficult to confirm compliance with twist geometry standards. As a result, trains continued operating on tracks with poor geometry.
4. Although drainage ditches were present in the derailment section, they appeared ineffective. Water remained in the ballast even after several rain-free days. The presence of water mixed with silt hindered drainage, reduced ballast strength, and contributed to track irregularities.
5. The TRC's inspection systems are unable to detect the reduction rate of rail cross-sectional area, from Category A inspections to routine track patrols. As a result, defective rails could not be identified or corrected promptly. Furthermore, there are no regulatory standards regarding railhead wear.
6. The Railway Bureau’s periodic and non-periodic inspection frequencies on the Pingxi Branch Line were insufficient to identify this segment as high-risk promptly and to mandate corrective action from the TRC.

Other Findings

1. The TRC did not adjust the maintenance cycle for wheel diameter on DRC1000 series vehicles to correspond with the specific operating conditions of the Pingxi Branch Line. This resulted in wheel wear exceeding allowable limits prior to the next scheduled maintenance.

Safety Recommendations

To the Ministry of Transportation and Communication (MOTC)

1. Review and revise the “Track Maintenance and Inspection Regulations for 1067 mm Gauge” to clearly define the criteria for guard rail installation and to include standards for railhead wear.

To the Railway Bureau

1. Review and strengthen the inspection mechanisms for both track maintenance on the Pingxi Branch Line and maintenance practices of DRC1000 series rolling stock.

To the Taiwan Railway Corporation, Ltd.

1. Evaluate incorporating wheel load as a vehicle maintenance indicator and establishing a wheel load management system.
2. Improve drainage functionality along the Pingxi Branch Line.
3. Establish repair deadlines for rectifying track irregularities exceeding emergency maintenance standards and reinforce post-maintenance inspection procedures.
4. Review and improve rail wear inspection methods to ensure compliance with regulatory standards.

The full investigation report is available for download at the TTSB website: https://www.ttsb.gov.tw/english/18609/28185/40805/post

Ya-Ting Chang, Director

Secretariat Office

Tel: +886-2-7727-6210

E-mail: yating@ttsb.gov.tw

Jackie Chen, Chief Investigator

Railway Occurrence Investigation Division

Tel: +886-2-7727-6262

E-mail: jackiechen@ttsb.gov.tw