From their beginning American railroads developed medical arrangements to care for the large number of workers and passengers they killed or injured. After the Civil War, both labor unrest and liability concerns led them to expand and formalize these arrangements, and three forms of organization arose. Western roads, facing an almost complete lack of medical facilities, developed employee-funded hospital organizations. In the east, companies created medical organizations under a salaried chief surgeon and contracted with local physicians to provide care. A third model, pioneered by the Baltimore & Ohio Railroad in the 1880s, devised a beneficial society that provided medical care and compensation for injured workers. Although these organizations involved both contract practice and group hospitalization, the AMA seems to have ignored them. In the 1880s railroad physicians developed their own organizations, including the National Association of Railway Surgeons, in which they discussed problems of professionalization and such medical matters as "railway spine." Concern with costs and labor turnover also led the carriers into preventive medicine. Some roads provided smallpox and typhoid vaccinations, campaigned against malaria, improved passenger-car sanitation, required physical examinations of their employees, and trained them in first aid. By World War I, railroad medical organizations provided care to nearly two million employees and employment to about 10 percent of all physicians.