Technology

One of the most interesting aspects of historic preservation of anything is that it's an extremely new concept. The modern view of it is about a single lifetime old, dating back to the early 20th century. Historic structures were nothing but old buildings and would be torn down with the materials repurposed as soon as there was a better use for the land or materials. Most historic buildings that date to the 19th century and earlier are standing not because people invested significant time and money into maintaining a historic structure as it originally was but because people were continuing to live, work, socialize or worship in the structure.

Preservation is entering a very interesting new phase right now particularly in transportation preservation as many of the vehicles in preservation have now spent significantly longer in preservation than they did in active service. There are locomotives that were preserved in the 50s and 60s who's early days of preservation are themselves a matter of their history. There are new-built replicas of locomotives from a hundred years earlier that are now a hundred years old. In railroad preservation there's also now the challenge of steam locomotives being so old and so costly to maintain that some museums are turning to building brand new locomotives based on original blueprints