dome car was first developed in the 1880s; known at the time as the "birdcage car", it was used on an 1882 sightseeing tour on the Chicago, Burlington and Quincy Railroad. In 1891, T. J. McBride received a patent for a car design called an "observation-sleeper"; illustrations of the design in Scientific American at the time showed a car with three observation domes. Canadian Pacific Railway used "tourist cars" with raised, glass-sided viewing cupolas on their trains through the Canadian Rocky Mountains in the 1920s. These dome car designs did not prove successful, and further refinements to the idea didn't come for a few decades. The first successful dome cars were conceived by Cyrus Osborn of General Motors Electro-Motive Division (EMD). In 1944, while traveling in an EMD-built Denver & Rio Grande Western locomotive through Glenwood Canyon in Colorado, he recognized the wonderful views the passengers could enjoy from a panoramic dome. His idea was to provide a full 360-degree view from above the train in newly built "Vista-Dome" cars. Mr. Osborn took the idea to the Chicago, Burlington and Quincy Railroad (CB&Q). The CB&Q took a stainless steel Budd-built coach and rebuilt it at their shops in Aurora, Illinois, with the Vista Dome imagined and sketched by Cyrus Osborn. The dome area featured seats that were positioned lengthwise in the cabin facing double-pane windows which were designed to improve insulation. This first Vista Dome was called, appropriately, Silver Dome. On July 23, 1945, the car was tested in the consist of the Twin Cities Zephyr. Vista Domes quickly found their way into many Burlington Zephyr consists, culminating in 1949 with the inauguration of the California Zephyr. Soon after Silver Dome entered service, railroad managers and passenger train executives met to discuss the merits of the dome car design. In the United States, domes could only be readily used on railroads west of the Mississippi, due to lower clearances in tunnels in the eastern USA. (In Canada, Canadian Pacific would run its domes from coast to coast.) The managers also noted that the passenger carrying space was regarded as non-revenue space because the managers believed that passengers would not want to spend their entire trip in the domes. These factors and the added costs of car construction in adding stairs, two levels of car floors and air conditioning increased the costs to railroads that chose to operate dome cars. Despite