Craft's excellent post brings up some important spciifics regarding the rebuilding historic objects. "Preservation" from what I remember is defined as conservation of all remaining material, and a very strict rebuilding to its exact historic construction. "Renovation" is a looser definition. It allows repacement
of subassemblies with new or more durable materials. It also allows for limited introduction of modern materials and appliances that could enhance the longevity and/or conservation of the historic display.
A good example of a historic preservation is North Pacific Coast Ry. #13 ,the "Sonoma", an 1870s Baldwin 4-4-0 on display at the California State R.R. Museum at Old Sacramento. A good example of historic renovation is Dan Markoff's "Eureka", an almost identical locomotive that is very close to what it was in the early 1880s, but has a few items on it that might not have been on the engine in 1875. Sometimes the line between the two definitions is slippery. The buildings in Old Sacramento are beautiful renovations, but necessarily have electric lights, running water, motion detectors, fire alarms and other modern devices that aid in the conservation of old buildings. Historic fidelity can eith collide with modern practicality of dovetail with it. Obviously having all the buildings lit with whale oil lamps would be asking for serious trouble.
The 315 generated similar discussions and arguments. I wanted to install the more modern 6-ET air system on the locomotive, but the historic system was 1-A and that is what is on the locomotive. However, I did prevail to put a high-cfm filter on the air system to protect the feed valves and air brake applianceses.
FInally there was a discussion to reinstall the Priest Flanger apparatus on the pilot, or a mock-up of the same. This discussion was tabled until the completion of the project. All-in-all, 315 will be extremely close to what it was as a working road locomotive in 1939 or '40. However, I am reasonably sure it would be properly desscribed as a "renovation, not a "restoration"
