TRAX moves a lot of people from one end of the Salt Lake Valley to the other every year. Our light rail system opened in December, 1999, but it wasn't Salt Lake's first mass transit system. In fact, most Utahns are probably unaware that half of Salt Lake City residents took mass transit every day back in 1914. That's right...that year people took 38.9 million trolley rides.

Some Utahns might remember the trolley cars that rolled through the streets of Salt Lake City. The rest of us can only imagine! Check out these old trolley car photos from the past:

Back in the late 1800s, the streets of Salt Lake City were muddy, and mules and wagons transported residents from one place to another.

One entrepreneur started the very first trolley system, which involved a mule pulling a wagon along tracks. It was expensive to ride, and very slow.

In the 1890s, Salt Lake City began lighting up. Electricity was in town, and it brought all kinds of technology upgrades, including an electric trolley system.

In the beginning, four different trolley car companies operated in the city. The competition was fierce, and led to some pretty underhanded behavior.

Some trolley car companies put down new lines, only to have another company come right behind them and tear them up.

In 1901, the companies all consolidated, and in 1906, major upgrades were completed.

Long before Trolley Square became a shopping center, it served as a garage for trolley cars. The garage was part of the massive upgrade, which also included another 80 miles of track and brand new, steel streetcars.

The new trolley system still had its problems. Sometimes the cars fell off the tracks, or the overhead wires broke. The unheated cars were also freezing cold during the winter months.

In their heyday, trolley cars provided transportation for millions of people every year, and the trolley system included 145 miles of track.

In 1914, a record was set - 38.9 million passengers took rides on the trolley that year. By comparison, in 2014, TRAX had just 19.5 million rides.

Sadly, the trolley system met its match when people began buying automobiles, and the city purchased buses for transit.

By the 1941, only one trolley remained. The last line stretched ran from the intersection of 900 S. 1300 E. up to the University of Utah, and it closed up in 1946.

You can learn more about Salt Lake City's trolley system at the Trolley History Museum at Trolley Square.

The museum's normal operating hours are Thursday and Friday evenings from 5 p.m. to 9 p.m. Admission is free!

Do you have memories of Salt Lake's trolley cars? We'd love to hear your stories in the comments!