Mid-engine school buses During the mid-1950s, Crown made several changes to the Supercoach. In 1954, the company made the Cummins NHH available as an option, producing the first diesel-engined school bus. In 1955, Crown developed the largest school bus in the United States. In expanding the bodyshell to 40 feet (then the maximum for both school buses and motorcoaches) and adding a second rear axle, Crown raised the seating capacity from 79 to 91 passengers. As a later option, some school districts ordered the Supercoach with a 16th row of seats, further expanding seating to 97 passengers; as with its Gillig counterpart, the 97-passenger Supercoach is the highest-capacity school bus ever sold in the United States. From the 1950s to the 1970s, school bus production on the West Coast evolved separately from the rest of the United States, with the Crown Supercoach and the similar Gillig Transit Coach having a near-monopoly of the school bus segment in California and a large share of the rest of the West Coast. Outside of the region, many operators continued use of lower-capacity conventional-type buses based upon truck chassis. For users seeking lower-capacity buses on the West Coast, in place of developing an all-new model line from the ground up, both Crown and Gillig chose to serve as the West Coast distributor for other manufacturers. At various times, Crown would market Wayne, Blue Bird, and Thomas Built Buses in California. Sharing much of its underlying structure with the Crown school bus, the intercity Crown Supercoach was marketed with several configurations. Along with an underfloor configuration, Crown also produced a rear-engine version, as well as a raised-floor configuration (along with a version similar to the Scenicruiser); the latter two provided for increased luggage space. To supplement its motorcoach offerings, in 1969, Crown became one of the first distributors of Quebec-built Prevost motorcoaches in the United States. The Firecoach was produced through the 1960s and 1970s with relatively few changes. While sold primarily across the West Coast, examples of the Crown Firecoach were purchased by fire departments across the United States. In 1965, a roof was made standard for all Firecoaches, in the interest of firefighter safety. 1980–1991: Decline In 1979, the Brockway family sold Crown Coach Corporation to a local truck distributor; this began a sequence of ownership changes. Due to slow sales, Crown ended production of the motorcoach version of the Supercoach in 1980,