LASER CUT CAR CARD BOXES!

I have rolling stock mainly consisting of older tyco and some trainset quality life-like cars that I am using for my switching layout. They all not have body mounted Kadees and the question remains should I convert them to Metal Wheelsets? I have 18 cars being used on the "layout" and was curious what is the cheapest/most economic way to get enough for them all? I as many of you know have an extremely small budget so whatever help you can give would be appreciated! 

A couple questions for the community on industry yards:

How does a large industry yard like those at a paper mill with its own plant sitcher operate?

Are tracks allocated based on commodity (track 1 - wood chips (loaded / unloaded), track 2 - addtives, etc...) for ease of sorting by the plant switcher, or are they all just 'storage' (cars placed on any unused track in the yard) except for a designated pick-up and/or set-out track for the local switch job?

Ok, so my steam locos have dumped their ashes, which in turn have been loaded up into an old mangy hopper car -- but then, what next? What did the railroads of with all those ashes? Was there someone who could get value out of those, were they just hauled and dumped somewhere, or...what? Is anyone familiar with how these moved after they left the engine servicing area?

Work on the brige, scenery  and operations.

https://m.youtube.com/watch?v=nV8HMqudmQA

​https://m.youtube.com/watch?v=gQEZ7HIkOss