U-form

This is the functional or unitary form of business-organization that first developed with the railroads in the United States in the mid-1800s. It is the now conventional structure composed of a central management unit and several functionally organized departments. This structure was the great organizational achievement of the nineteenth century when, as scale and complexity increased, individual entrepreneurial forms gave way to those that relied on technical expertise, specialization, and salaried managers: a full-fledged corporate bureaucracy. (Scott & Davis, 2007, pp 348).