Boiler and Superheater Parts Question

The recent thread about the 464 and the possibility of re-installing her superheater brought to mind some questions. Did steam locomotive manufacturers, given the individual nature of many of their locomotives, maintain a stock of spare parts such as flue sheets, flues, superheater elements and the like? Or were the railroads on their own to make such items when needed?

For that matter, what sort of parts inventory did manufacturers keep in stock to service and repair their products?

Which brings up another question. Was there any kind of warranty on a steam locomotive and what was it?

Ed