480063 Release Service Bulletin Dual Frauscher Bracket Failure Investigation

Date: Released 6/8/2025

Application: This service bulletin covers the mounting bracket (Comet PN#:400229 provided for application of the Frauscher zero speed wheel sensors to the Progress Rail Micro HBD.

Summary

Comet supplies a conversion kit to use Frauscher zero speed detectors for PRS HBDs. Recently, the field failure rate has warranted further inspection. Norfolk Southern (NS) technicians will inspect current installations, and Comet will replace failed brackets in the 90-day investigation period. Appropriate action will be agreed upon based on the discovered scope and severity of the problem.

Background

Comet has provided NS with a kit to convert the PRS Micro HBD to use Frauscher Zero Speed wheel sensors instead of the wheel sensors provided with the detector. In the months preceding the release of this bulletin, the reported failure rate is higher than normal. This bulletin is intended to collect information about the scope and severity of the problem.

Affected Units

Over 450 units have been shipped since the introduction of this product in 2018. All units in the field are being considered as possible issues.