Before I type my thoughts, I want you to understand I don't mean to question your thinking or logic and I am not criticizing you in any way. I feel compelled to say that as nastiness towards one another is frequent on this forum. I say this only to, hopefully, offer help.
what I need are some specifics with regard to the restoration needs of railroad equipment
It seems to me you may be seeing too much into this restoration procedure. Any restoration project, be it railroad equipment, historic buildings, antique cars, vintage trucks, etc. involves the same general skill sets, none of which are all that specialized for any one industry. In all the to do examples you've listed, I didn't see a single one that was specific to railroad equipment only.
For example, you mention wood on the roof of a steam engine. An experienced woodworker should be able to handle that and get you a price quote. Sandblasting, repairing and replacing the rotted steel can be done by a metal fabricator and he should be able to quote a price for that. A glazer or maybe even a mobile auto glass replacement company can replace the missing windows. I don't know what the armrest was made of, but a picture or sketch of the item with dimensions given to a woodworker or fabricator or upholsterer or whom ever will give the person what they need to figure out a quote for you. You mentioned tiles in the observation car. Get a few tile contractors in there to look at it and give you some quotes.
As Aji-tater suggested, break each project down into it's individual pieces and prioritize them, then call in professionals in each of those fields...carpenters or cabinet makers, welders, tilers, glazers, upholsters, etc... and get quotes from them. I think you will be able to find all the answers you need for pricing and qualified restoration work right in your back yard if you view each item for what skill set or trade it requires rather than viewing the whole restoration as a 'railroad' related item. I wouldn't be surprised to find you have members of many of these needed trades right in your own membership.
Hope I haven't insulted you in any way. The fact is I'm envious of you. I would love to pass the days away restoring rail equipment! Best wishes.