Electrified streetcars posed an attractive target for striking unions like the Amalgamated Street Railway Employees of America. Unlike factory buildings, streetcar routes and cars were spread out and difficult to protect. The routes went through the working class neighborhoods of cities; riders tended to be sympathetic to union causes. Their overhead lines and physical tracks were vulnerable to sabotage. And their function as transportation for workers in other industries opened the possibility of leveraging a transit strike into a general strike, as in the Philadelphia trolley strike and riots of 1910. Streetcar strikes rank among the deadliest armed conflicts in American labor union history. Samuel Gompers of the American Federation of Labor called the St. Louis Streetcar Strike of 1900 "the fiercest struggle ever waged by the organized toilers" up to that point, with a total casualty count of 14 dead and about 200 wounded, more than the Pullman Strike of 1894. The casualty count for the San Francisco Streetcar Strike of 1907 saw 30 killed and about 1000 injured. Despite the transit disruption, which sometimes lasted for months, and despite the fact that many of the casualties were passengers and innocent bystanders, "the strikers invariably enjoyed wide public support, which extended beyond the working class." The owners' tactic was simply to keep the routes running. To counter hostile crowds, the line owners turned to strikebreakers. Foremost among them was James A. Farley, who specialized in streetcar strikes—he claimed to have broken 50—and was said to command an army of forty thousand scabs to be deployed anywhere in the country. Much of the violence of the 1907 San Francisco strike was attributable to Farley, who reportedly cleared $1 million there. He was doing more than $10 million in business by 1914.
1891, Detroit, Michigan, where strikers had the vocal support of Mayor Hazen S. Pingree, part of his administration's long successful struggle against local traction companies
1913, Buffalo, where two regiments of the National Guard were called out to quell a full day of rioting and mob violence, with several wounded by gunfire, and widespread property damage
Scenes of streetcar strikes, and the friction between owners and workers, appear in contemporary fiction such as Theodore Dreiser's Sister Carrie of 1900, and William Dean Howells' A Hazard of New Fortunes of 1890.
