The railway men are divided into three groups. One group comprises the Brotherhood of Locomotive Engineers, the Order of Railroad Conductors, the Brotherhood of Firemen and Enginemen, and the Brotherhood of Railroad Trainmen. These are the oldest and strongest railway men's organizations and do not belong to the American Federation of Labor. A second group are the shopmen, comprising the International Association of Machinists; the International Brotherhood of Blacksmiths, Drop Forgers, and Helpers; the Brotherhood of Railway Carmen of America; the Amalgamated Sheet Metal Workers' International Alliance; the Brotherhood of Boilermakers and Iron Ship Builders and Helpers of America; the International Brotherhood of Electrical Workers; and the International Brotherhood of Stationary Firemen and Oilers. A third and more miscellaneous group are the Brotherhood of Railway Clerks, the Order of Railway Telegraphers, the Switchmen's Union of North America, the International Brotherhood of Maintenance of Way Employes and Railroad Shop Laborers, and the Brotherhood of Railway Signalmen. The organizations comprised in the latter two groups belong to the American Federation of Labor. For the period from 1898 to the outbreak of the War, the organizations, popularly known as the "brotherhoods," namely, those of the engineers, conductors, firemen, and trainmen, are of outstanding importance. The brotherhoods were unique among American labor organizations in that for many years they practically reproduced in most of their features the sort of unionism typified by the great "Amalgamated" unions of the fifties and sixties in England.[59] Like these unions the brotherhoods stressed mutual insurance and benefits and discouraged when they did not actually prohibit striking. It should, however, be added that the emphasis on insurance was due not to "philosophy," but to the practical consideration that, owing to the extra hazardous nature of their occupations, the men could get no insurance protection from ordinary commercial insurance companies.