Transformer roller assemblies are not railway rolling-stock parts when their design and use are confined to electrical transformers.

Heading 8607 applies only to parts and accessories identifiable as suitable solely or principally for railway or tramway locomotives or rolling stock. Roller assemblies designed exclusively for transformers did not meet that test because they lacked railway-specific features such as braking and lubrication and were intended for transformer use, not railway vehicles or their parts. Classification therefore followed their true function and intended use under Heading 8504 rather than Chapter 86. The earlier view treating such assemblies as rolling-stock parts was overruled, and the assessee's classification outside Heading 8607 was upheld.

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Issues: Whether roller assemblies designed for use with transformers were classifiable under Heading 8607 as parts of railway or tramway locomotives or rolling stock, or under Heading 8504 as parts of electrical transformers.

Analysis: Heading 8607 applies only to parts and accessories that are identifiable as being suitable for use solely or principally with railway or tramway locomotives or rolling stock. Note 3 to Section XVII excludes from Chapter 86 parts and accessories not suitable for such exclusive or principal use. The roller assemblies in question were designed solely for transformers, lacked features such as braking and lubrication associated with railway rolling stock, and were not suitable for use as railway vehicles or their parts merely because they moved on rails. Classification therefore had to be governed by their true function and intended use, which aligned them with transformer parts rather than railway rolling stock.

Conclusion: The roller assemblies were not classifiable under Heading 8607 and were not parts of railway or tramway locomotives or rolling stock; the reference was answered against Revenue and in favour of the assessee.

Final Conclusion: The earlier view treating such roller assemblies as railway rolling-stock parts was overruled, and the assessee succeeded in obtaining classification outside Heading 8607.

Ratio Decidendi: For Chapter 86 classification, a part must be identifiable as suitable solely or principally for railway or tramway locomotives or rolling stock; an article designed exclusively for another machine cannot be brought under Heading 8607 merely because it moves on rails.

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