The Nevada State Railroad museum has published several different restoration reports over the years, for example the Restoration Feasabilty study for the McKeen car... ) others were for the various wooden freight and passenger cars, and I believe for the a couple of the V&T 4-4-0's. These are the research papers into the objects history done before the actual restoration, not just documents about the work..
They cost about $50.00 each, so your price point is not far off.
The California State Railroad museum has their restoration reports in the library, and charge a copy fee for copies...
Randy Hees
www.spcrr.org