The Mt. Wilson occasionally gives engineering tours of the two telescopes, the 60" and the 100". I was lucky enough to do so about a year ago. The mechanics and precision that went into them is amazing considering they were built some 100+ years ago and, as previously mentioned, the parts were hauled to the mountaintop by mules (and later by one of the first ever Mack trucks). Sighting the telescopes was done by multi-fold periscopes from which one could read a precision dial located on the telescope mount down in the basement, and yes, the observer sitting at his cold station had to constantly tweak the position of the film holders to keep them aligned with a guide star. Electricity was provided not by city power, but by a huge lead-acid battery bank that was charged during daylight hours by a generator powered by a recently restored two-cylinder engine. They couldn't run the engine at night since the vibration would affect the telescopes located hundreds of yards away.
I highly recommend the tour. Do it while you can, the docents aren't getting any younger.