 Although the concept would be later popularized by the Pullman Company, Wason was the first to manufacture sleeping cars in America.Wason's earliest clients included the Michigan Southern Railroad (1846–1855), Alton Railroad, Central Railroad of New Jersey, and Boston and Maine Railroad, as well as foreign operators such as the State Railway of Chile, and Egyptian National Railways, providing the latter with 161 cars as well as an ornate state carriage for Sa'id of Egypt, the viceroy at that time.. By 1867 the company had about 300 employees.The company made the first passenger coaches used on the Transcontinental railroad.