Minitrix BB 567422 SNCF Serie Mode D'emploi page 11

Information about operation
As a general rule locomotives with sound require very good
current pickup. We thus recommend using turnouts with
polarized and current-conducting metal frogs.
General Note to Avoid Electromagnetic Interference:
A permanent, flawless wheel-rail contact is required in
order to guarantee operation for which a model is designed.
Do not make any changes to current-conducting parts.
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