Appears to be the bible on this and other instruments of the type. Thompson-type indicators were made by many companies. The best known are the American Steam Gauge Company, Schaeffer & Budenberg, James Robertson & Sons and Dobbie McInnes. Please see my other related instruments.
The item "AMERICAN (THOMPSON) STEAM GAUGE INDICATOR in BOX, COMPLETE with BOOK" is in sale since Wednesday, April 8, 2020. This item is in the category "Collectibles\Transportation\Railroadiana & Trains\Hardware\Whistles, Bells & Horns". The seller is "valveland" and is located in Ewing, Kentucky. This item can be shipped to United States, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Singapore, Switzerland, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Chile, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Bangladesh, Brunei darussalam, Bolivia, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Liechtenstein, Luxembourg, Monaco, Macao, Martinique, Nicaragua, Pakistan, Paraguay, Uruguay, Philippines, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Turks and caicos islands, Canada, South africa, Colombia, Antigua and barbuda, Saint lucia, Barbados, Bermuda, Cayman islands, Sri lanka, Maldives, Oman, Reunion, Montserrat.