Brake is a safety critical system for railway vehicles and brake failures have caused many catastrophic accidents in the history. For example, On October 4, 2018, incorrectly configured air brake hoses caused a moving freight train collided a stationary train at Granite Canyon with 2 people killed and 66 cars derailed. The train derailment in Quebec on July 6, 2013 that killed 50 people was caused by an employee not setting the brakes properly. On September 12, 2008 Metrolink commuter train and a Union Pacific freight train collided head-on at 84 miles per hour, killing 25 people and injuring 135 in Los Angeles. The investigation shows the probable cause is that the Metrolink engineer failed to apply brake in response to the red signal. Brake failures could be caused by human error, faulty systems or overloading. Detailed accident investigation reports are available and National Transportation Safety Board (NTSB) also makes safety recommendations to Federal Railroad Administration and the industry. However, there is limited research on how to improve the brake safety from the perspective of design, system integration and safety analysis. In this paper, a summary of major accidents related to braking in the United States is provided as well as the root cause analysis and safety recommendations. Then a framework of braking safety design and analysis is introduced on how those common braking failures can be mitigated at the beginning of system design. The framework includes four parts: failure alarming system, safety design, safety analysis and preventative maintenance. For failure alarming, according to the severity level, the failures will be notified to the operator, to Operation Control Center (OCC) or saved for the maintainer. The failure codes are marked with different colors so the operator/OCC would know what actions to take, i.e. stop the train immediately, check at the end of the trip, check at end of the day’s service or check at the scheduled maintenance. For safety design, redundant design for fail-safe feature, automatic braking to eliminate human errors, weight control, ergonomics design for easy operation and maintenance are discussed. Detailed design concepts and successful applications are illustrated. In the safety analysis section, Preliminary Hazard Analysis (PHA) as a semi-quantitative analysis, Failure Modes, Effects, and Criticality Analysis (FMECA) as a bottom-up method and Fault Tree Analysis as a top-down method are used. The hazards details, system assurance actions and closure references are recorded in the Hazard Tracking Log (HTL) to ensure all the safety related items are well tracked and documented. Preventative Maintenance (PM) which is regularly performed on the brake components to lessen the likelihood of failing is also discussed in combination with the reliability prediction and safety analysis for a balance of safety and economy. This braking safety design and analysis framework has been successfully implemented in many projects worldwide by CRRC Corporation Limited. The safety design framework and principles introduced in this paper can also be applied into other railway systems, such as Propulsion, Signaling, Doors, etc. and may provide insights to similar industries such as automotive, energy and so on.  


Braking Safety Design and Analysis for Railway Vehicles

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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