Properly operating a steam locomotive is a frightfully complicated task. Unlike most modern engines that essentially have only a starter and throttle, steam engines require careful attention to temperatures and pressures in the firebox, boiler and steam chests. Water levels, fuel flow, lubrication, replenishment of fuel, water and sand also require the attention of the (usually two-man) crew.
A steam locomotive operates differently under different weather conditions: temperature, humidity, rain or ice all significantly affect its operation. The crew must anticipate changes in load caused by hills or curves. The mechanism is very slow to respond to changes in settings and it can be extremely difficult to restore normal operation if any single parameter slips out of tolerance. Operating a locomotive at 30 mph is a completely different thing than operating at 60 mph. It took years of on-the-job training for an engineer to learn to safely control a steam locomotive.
A Pennsylvania Railroad steam locomotive (#460, the “Lindbergh Engine”) pulling a tender, baggage car and coach car, is said to have reached a speed of 115 mph on June 11, 1927. I am amazed by the skill of the crew, and the level of trust that they would place in the metallurgy, assembly and maintenance of the locomotive, cars, wheels, tracks, crossings, etc.
There is no reason to believe that a Replicated steam locomotive would not be fully functional. But it was designed to be operated by a trained crew and run on properly installed and maintained tracks. If I were to need to actually operate my new locomotive I would need to be able to replicate an entire infrastructure of physical objects as well as draw forth the knowledge and skills needed to use this technology.
Many technologies have fallen into disuse - sometimes through obsolescence, sometimes through simple neglect. The ability to use the technology that will eventually be embodied in the Replicator’s “Universal Library Of Everything That Has Ever Been Made” will depend on that library containing much more than physical construction specifications.
We need to think about the concept of the Operator’s Manual in the same radical way we think about disassembly and recycling. The manual needs to be actually useful in describing how the object is intended to be used and what standard level of background knowledge is expected of the user. Making documentation for a truly broad audience does not mean copying the same unintelligible instructions into seventeen different languages.