Dome cars could be described as the ultimate traveling experience aboard a passenger train and their addition to such famous trains as the California Zephyr and Empire Builder vastly increased their popularity by giving patrons unequaled vistas of the passing scenery of the Rocky Mountains and Pacific Northwest. During its early years Amtrak continued to provide dome car service via the used equipment it received from the railroads. Today, though, that is not the case. However, they do operate a version of these cars in the way of Superliners, which are double-decked cars that serve in the same function as domes with lounge-seating accommodations on the upper floors to passengers can watch the passing scenery from the highest vantage point. Outside of Amtrak various tourist railroads and other groups occasionally operate domes in excursion service. Finally, the new Pullman Rail Journeys has placed a dome car back in service which runs on select Amtrak trains.
Dome cars have their earliest beginnings dating back to the late 19th century. However, these early designs were not successful and it was not until the streamliner era that the car truly came of age. In the mid-1940s Cyrus Osborn, vice president and general manager of General Motors' Electro-Motive Division conceived what he dubbed a Vista Dome car built from a Budd Company coach, which featured a second-floor solarium for an unprecedented 360 degree view of the surrounding landscape. By the 1950s dome cars were all of the rage and almost all named trains across the country carried some type or design of them.
Vista-Domes became a trademark on passenger trains of the Chicago, Burlington & Quincy and particularly the California Zephyr, which used dome cars almost exclusively so that passengers could be afforded maximum views of their trip through the Rockies and Feather River Canyon. During the CZ’s “Golden Years” between 1949 and 1970 each train was equipped with no less than five of these cars, very uncommon for even the most popular trains of the day. For even better sightseeing these Vista-Domes were setup in everything from diners to sleepers. What’s more,the train’s timetable was arranged in such a way that it always traveled through the most scenic parts of the trip (west through Colorado) during the day so passengers didn’t miss a thing at night or while sleeping.
Dome cars were mostly featured on passenger trains of the western railroads due not only to the wide open vistas afforded but also because height restrictions were not such an issue as they were back east, making dome cars in general rather rare although railroads like the Baltimore & Ohio made use of them the best the could by reducing the height of the domes (the B&O's version was dubbed the Strata-Dome and the first such car to operate in the east debuting in 1949). Perhaps the most unique twist on a type of dome car was the Seaboard Air Line's Sun Lounge equipped on its very popular Silver Meteor passenger train. Built in conjunction with Pullman-Standard the car was not actually a dome but featured a glass roof as dome cars could not navigate through the tunnels along the Potomac River (the train operated as far north as New York City in conjunction with the Pennsylvania Railroad).
In the west virtually every major railroad had its own version of a dome. The Union Pacific operated Domeliners (in which they featured dining services among other things), the Milwaukee Road and Santa Fe Super Domes (the Santa Fe also operated Pleasure Dome lounges and the popular Hi-Level cars on its El Capitan with second floor glass ceilings), the Great Northern Great Domes, and the Northern Pacific's aforementioned Vista-Domes (several eastern and western railroads operated the Budd Company's Vistas).
With passenger rail travel waning in the 1960s railroads began to cut back on the service where and when they could. As a result, save for a railroad's most prominent passenger train(s), most runs that operated dome cars lost the service to curb operating expenses. Until the end, however, when Amtrak took over intercity passenger rail operations in the spring of 1971 some railroads remained determined to provide top quality service on their trains such as the Rio Grande's then Rio Grande Zephyr, the Santa Fe's Super Chief, and then Burlington Northern's Empire Builder (which used a combination of former NP and GN equipment).
Today, Amtrak has long abandoned the traditional dome cars and replaced them with more utilitarian Superliners, which afford more seating for the same experience. Outside of the occasional excursions offering original dome car service of special note is the new Pullman services provided by Pullman Rail Journeys, which brings back the classic, bygone era of passenger rail travel in 2013. Despite being expensive the company spared no expense in once again offering the traveling public a chance to experience a journey over the rails just like it was before Amtrak.
For more reading about dome cars the book American Passenger Train Equipment: 1940s-1980s by author Patrick Dorin provides a very nice general history of classic car types used in service (predominantly during the streamlined era) featuring many drawings and detailed information on several. Also, the book The Cars of Pullman from author Joe Welsh, Bill Howes, and Kevin Holland. As the title implies the book details and highlights the various types of cars Pullman built throughout the years, along with giving a general history of the company in the process.