On most steam excursions over any good distance with larger power, an auxiliary tender is used. Were auxiliary tenders plumbed to work with the independent brake with the locomotive, or were they just handled as another car on the train? Whenever a diesel is behind the engine, how typical is it for the braking on longer grades to use the dynamics rather than retainers? I realize there can be a thousand different scenarios to answer the question, but I was curious.

Thanks

Obviously plumbed for the train line, the tender is a semi-permanent connection so could always be loco-braked. Good question tho, like the N&W used accessory tenders. I would think if the aux tender was plumbed for trainline the engine-tender would have enough oomph to handle engine braking while disconnected with the train.