Given the task definition and input, reply with output. In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: Steamtown, U.S.A., was a steam locomotive museum that ran steam excursions out of North Walpole, New Hampshire, and Bellows Falls, Vermont, from the 1960s to 1983. The museum was founded by millionaire seafood industrialist F. Nelson Blount.  The non-profit Steamtown Foundation took over operations following his death in 1967. Because of Vermont's air quality regulations restricting steam excursions, declining visitor attendance, and disputes over the use of track, some pieces of the collection were relocated to Scranton, Pennsylvania, in the mid-1980s and the rest were auctioned off. After the move, Steamtown continued to operate in Scranton but failed to attract the expected 200,000–400,000 visitors.  Within two years the tourist attraction was facing bankruptcy, and more pieces of the collection were sold to pay off debt.
In 1986, the United States House of Representatives, under the urging of Pennsylvania Representative Joseph M. McDade, voted to approve $8 million to study the collection and to begin the process of making it a National Historic Site. As a result, the National Park Service (NPS) conducted historical research on the equipment that remained in the Foundation's possession. This research was used as a Scope of Collections Statement for the Steamtown National Historic Site.  The scope was published in 1991 under the title Steamtown Special History Study. The report provided concise histories of each piece of equipment and made recommendations as to whether or not each piece belonged in the soon-to-be government-funded collection.
By 1995, Steamtown had been acquired and developed by the NPS with a $66 million allocation. Several more pieces have been removed from the collection as a result of the government acquisition. Part of the Blount collection is still on display at the Steamtown National Historic Site in Scranton.
What is the name of the research conducted by the NPS after it was released in 1991?