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Solid-State Welding of Signal Wire Attachment

Document Series
Research Results
Federal Railroad Administration
Report Number
RR 21-02
Subject Track
Signal wire bonding, solid-state, welding, portable, PTC

More reliable signal wire attachments can reduce uncertainty, improve safety, and reduce operational costs. This report investigates the causes of failures at these attachments and develop an alternative signal wire-to-rail attachment process. EWI modified an earlier design of the brass stud to reduce the weld area and then developed new friction welding process conditions for the new design. The smaller weld area enabled the design of a small and lighter second-generation prototype welder. The design of the studs also allowed for wires to be removed and reattached during maintenance activities, without the need to produce an additional weld. Attachments made with this solid-state welding process prevented damage to rail and provided equal or better attachment strength and electrical resistance compared to existing methods.

Last updated: Monday, March 22, 2021