This week we head back seventy three years to January 3, 1937 when the 200-inch telescope's prime focus elevator arrived on Palomar. The photo shows the prime focus elevator on the truck that bought it here, parked just outside the dome of the 200-inch telescope.
You can see the prime focus elevator as it is installed today in this modern photo below:
The elevator is bright thing middle right in the image.
Recall, that people used to observe with the 200-inch telescope by actually riding inside it. Even though those nights are long gone (the observer sits in a nice warm room) the prime focus elevator still is the preferred mode of transportation to get someone to the upper part of the telescope or dome.
You can hear the prime focus elevator in action in a podcast that I did last year.