Rick,
Your Uncle Bob did this for many, many years and it was one of the ways that he raised money to keep the museum going. He auctioned off spikes, lanterns, switch locks and keys, paper items, uniforms and many, many books (look familiar in the catalog?).
Many of the items are donated by railfans or their estates. The Museum staff goes through the bequeathed items to review whether the Museum has these items on hand or if they are duplicates or triplicates or any other multiple.
If the Museum all ready has these items as part of their collection, then the items are released for auction. This allows railfans to complete their personal collections and raises a goodly amount of money for the museum itself. The other ramification is that if a particular railfan passes away, the collection that they may bequeath to the CRRM may also generate funds from the same item several times.
They're not just auctioning whatever they find, they are auctioning surplus. Just as you can't keep everything, you can't keep multiples of the same stuff. After all, how many copies of Cafky's Colorado Midland do you need with all of the same information in it? Two at most.
Don't fret, the auction is a long time and honored tradition at the Museum. Your Uncle Bob started it.
It is not a noisy live auction but a mail auction where the bids are sent via mail and the highest bid gets the item. There is a decorum and a process to it.
Rick Steele