RSSB2757 - T1161 Improvements to pantograph collector strips maintenance and to Automatic Dropping Device

This research focuses on:

1. Identification of cost-effective wear management strategies together with novel technological options for the collector strip.

The collector strips (or carbon strips) in contact with the OLE contact wire are the key component for the transmission of electrical energy between OLE infrastructure and the train. When the train is in motion, the strips are subjected to abrasion, electrical damage and fatigue eventually reaching their electrical and mechanical engineering limits. Hence, they must be regularly inspected and renewed (every 10-30 weeks ).

2. Improvements to the Automatic Dropping Device (ADD), a component of the pantograph.

Closely allied to the collector strips is the ADD, a feature of most pantographs operating on Network Rail infrastructure. Its role is to drop the pantograph in the event of significant damage to the pantograph head and/or collector strips as a protective measure. Further damage to the pantograph and strip could lead to dewirement.

Dewirements are a significant cost to the industry with safety implications (major dewirement incidents include injuries to passengers and/or track workers), but they primarily impact the performance and reliability of the service. This project will contribute to improving the reliability and performance of pantographs while reducing maintenance costs, system failure costs and to some extent, reducing dewirement delay costs and incidents.

T1060 (RSSB, 2018) looked at past dewirement cases and identified some causes and risks. The report recommended to review the effectiveness of the ADD system in preventing or mitigating the escalation of dewirement events. It noted that in a proportion of cases, the ADD position on the pantograph assembly is not always optimised for all rolling stock types. The project also identified opportunities to improve the ADD system.

Although, the definition of dewirement excludes regular wear and tear of OLE wires or pantograph carbon strips, they can become contributory factors to a more damaging event if not managed properly. There has been discussion at the VTE SIC around the need for an agreed industry position on the wear of pantograph collector strips. Network Rail Ltd is working with suppliers and the University of Milan to understand wear on the OLE, but no work has been undertaken to understand collector strip wear. Currently, there is an inconsistent approach across the industry to manage collector strip wear and no Whole Life Cycle (WLC) analysis is available to inform this.

The other highly relevant piece of research, T346 (RSSB, 2012), investigated the potential for improvements in electrification systems. It provided an assessment of the latest technological developments in both collector strips and ADD, laying down the areas for further improvements (e.g. alternative carbon material with lower wear rate and alternative ADD systems with faster response times).