I personally hate the word "restoration" because of it's range of interpretation and application.
You basically have a few limited options:
1. One is preservation - but solely preserving something for it's existing historical fabric generally requires some kind of protection from the elements, generally poor/degraded appearance and may not be operable/useable.
2. Rebuild/repair - allows a presentable appearance, may be resistant to the elements, and potentially allows for use/operation. Typically, traditional repair methods and materials are used when possible. However, safety, reliability, availability and budget often require the modern methods and materials to be used. The base historical fabric is somewhat maintained.
3. Recreations - Too often, the historical fabric is too far gone to reasonably salvage. The existing artifact is limited to being used as a pattern for a newly built copy often incorporating some reusable components and hardware. Similar to rebuild/repair, traditional methods and materials may be used when practical. In some cases, there is little of the original that can be reused, or may no longer even exist.
For example, what is residing a wood car or building including repainting? Railroad did it all the time. Every car, loco and building has been rebuilt many times in it's "real" life. Even if you match the wood, is using power tools considered traditional construction? As recently discussed, modern paint has changed several times and is a long ways away from paint used 20-50 years ago.
Every rail museum I know of generally uses a combination of the above methods. Bottom line, be grateful what actually exists and support those projects you are really interested in within your capacity to donate or volunteer.
IMHO
