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Resolving Thermal Incidents in Door Control Units (DCUs)

Project Summary

Identified and eliminated the root cause of DCU thermal incidents – preventing overheating, smoke release and door operation failures.

Designed and deployed a new power supply unit (PSU) – that improved thermal performance, communication stability and overall system reliability.

Successfully overhauled more than 3,000 DCUs – enhancing passenger safety and reducing service disruptions across the fleet.

Background

TP Matrix were contracted by a major train manufacturer to investigate and address a series of concerning incidents involving Door Control Units (DCUs) installed in their trains. These DCUs were experiencing numerous thermal incidents during operation that resulted in loss of door operation and the release of smoke into the door vestibule areas.

Additionally, it was discovered that the same faulty components within the DCUs were also creating electrical noise issues which caused communication system disruptions. The railway operator identified these incidents as a critical safety concern and sought a comprehensive solution.

Investigation process

TP Matrix Ltd initiated a thorough investigation to identify the root causes of the thermal incidents. The investigation spanned several months and involved multiple phases:

Initial Assessment

The TP Matrix team gathered information about the affected trains, the DCUs, and the incidents themselves. They reviewed technical documentation, fault reports, and maintenance records.

Testing

The TP Matrix engineers performed comprehensive testing on sample DCUs. This included analysing power supply unit (PSU) performance, thermal behaviour, and communication stability. They replicated operating conditions to simulate on-board scenarios.

Analysis of PSU

Through extensive testing and analysis, TP Matrix identified that the PSUs of the DCUs were operating below industry standards. These subpar PSUs were causing overheating, which led to the thermal incidents. The inadequate PSU design was also contributing to electrical noise issues and communication system disruptions.

Smoke Incidents

The investigation revealed that the overheating PSUs were releasing smoke in train carriages during some incidents. This posed a significant safety risk to passengers and the overall operation of the railway system.

The solution

Redesigning the PSU – TP Matrix’s engineering team developed an improved PSU design that met and exceeded industry standards for performance, thermal management, and stability.

Testing and validation – The redesigned PSU underwent rigorous testing, including EMC, Shock & Vibration testing, to ensure its reliability and safety under various operating conditions. Eight of the new PSUs were fitted to DCUs and were successfully trialled on two fleets in 2018 without any issues.

Rollout Plan – TP Matrix collaborated closely with their customer to establish a phased rollout plan for the new PSU design. So far over 3,000 units have been successfully overhauled to include replacing the PSU along with replacing ageing components in the units (capacitors, relays etc.) to improve the overall performance and reliability of the DCUs.

Results

The collaboration between TP Matrix Ltd and their customer has yielded impressive results:

Incident reduction – The new PSU design ended the occurrence of thermal incidents in the DCUs, eliminating overheating-related smoke and noise issues.

Improved communication – The enhanced PSU design positively impacted the communication systems within the trains, reducing disruptions and ensuring smoother operations.

Passenger safety – The elimination of smoke incidents improved passenger safety and onboard experience.

Operational efficiency – With the implementation of the redesigned PSUs, the train operator has experienced fewer service disruptions and improved overall system reliability.

Conclusion

TP Matrix’s diligent investigation into the thermal incidents of the Door Control Units showcases our technical expertise and commitment to safety. Through a combination of meticulous analysis, innovative redesign, and strategic implementation, we are successfully resolving the issues, ensuring the continued safe and reliable operation of vehicles for our customer.