The Great Trolley Riot of 1891
In 1891, the trolley companies in Detroit were exceptionally unpopular, refusing to electrify the horse-drawn trolleys, paying their drivers a pittance, and charging excessive fares. Eventually the workers went on strike, joined by dissatisfied commuters, which was met by the companies with trolleys full of armed strike breakers.
The public did not take this well. They ripped up trolley lines, blockaded streets with downed trees, and eventually rolled a captured trolley into the Detroit River. When the company owners went to Hazen Pingree and asked him to call in the state militia, he made no bones about the fact that he sided with the rioters, hardly a surprising response from His Honor. In the end the trolleys were electrified, fares dropped by 40%, and by 1922 the city had gained full control of the trolley lines.
This summary was drawn from a Michigan Citizen article dating from 2000 recently republished by the fine folks at VoiceofDetroit.net. A tip of the hat to Mythkateer Raum Vogel for pointing us to the article.