Thread # 453322 provides a draft of the 200 Series model timeline. Several of us are endeavoring to complete it along with other series, but it's time-intensive; and like you mentioned, the information is limited on this site and others. Use the search bar on the Vintage Forum page and copy/paste the thread number. In addition, you can perform model number searches by just entering them with "Eureka". Several frequent VL posters are also well-versed in the 200 Series, so if you post photos in this thread - including ones with the manufacturer's labels - they'll provide some details.
The Eureka 200 Series - and its later variation series 2000 (High Range), 1400 (Mid/Low Range), 1900 (later Mid/Low Range) 300 & 600 (Kmart exclusives), 4000 (Widetracks), & 5000 (High Range Self-Propelleds) - originated with George Walker's styling of the models S-246 & D-360 in 1947 and ended in 2017 with The Boss model 1934-B. The first to be equipped with the disposable bag feature was the S-255, which appeared on the sales floors in 1955.
It is, however, still produced as the Sanitaire Tradition (commercial/heavy-duty) line.
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