For all the well-deserved flak the MBTA receives for its regular service interruptions, unpredictable schedule and patchy coverage, it’s worth remembering that just a century ago, your morning commute might be delayed indefinitely over a case of equine flu.

Before cars, buses, subways and commuter rails, there was a time when Boston’s primary means of public transportation was horse drawn streetcars, commonly referred to as horsecars.

These open-air trolleys were attached to railroad tracks along the roads of Downtown Boston and Cambridge, not unlike the street-level portion of the Green Line’s western branches, but without engines or motors. Instead, their forward movement relied on horsepower.

The Massachusetts Historical Society dates Boston’s first operational horsecar back to 1856, traveling between Cambridge’s Central Square and Bowdoin Square in Boston’s West End. Over the next decade, the popularity of these equine trolleys grew until there were routes across the city.

The trolley cars varied in size, with some of the larger ones requiring teams of horses, while others used just one.

This was long before the days of the MBTA, when Boston had yet to establish any sort of government-run transportation system. The horsecars fell under the jurisdiction of twenty separate railroad companies, each vying for greater ridership.

Between the score of competitors, eight thousand horses were employed pulling trolleys throughout Boston during the nineteenth century, according to data from the Allston Brighton Historical Society. Eventually, these twenty companies were consolidated into the West End Street Railway.

At the time, the chief concern amongst residents regarding horsecars was the placement of tracks directly on the streets, which many felt would decrease the quality of the road, in addition to creating safety issues. But since horse drawn streetcars were faster and offered a smoother ride than any nineteenth century alternative, these skeptics were soon won over.

However, the horsecars weren’t without their problems. Feeding eight thousand horses was extremely expensive, resulting in high fair prices set at the mercy of private companies. Attempts to minimize horse-related expenses led to these companies overworking their horses, who often became ill and died. Whenever contagious equine diseases swept through the city, the entire transportation system would be forced to shut down.

In the end, the reign of horsecars was short-lived, lasting only three decades until the invention of the electric-powered streetcar, a faster, cleaner, more reliable option. The West End Street Railway gradually phased out its horsecars, replacing them with their electric counterparts and electrifying the tracks where the horses once traveled.

For a brief time, the company attempted to run both electric and horse drawn streetcars on the same tracks, until a team of horses was electrocuted, causing this idea to be abandoned.

Boston’s last horsecar line was a track along Marlborough Street in the Back Bay, which finally closed in 1900, a few years after the construction of the city’s first subway.